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June 2025 Earth Science Regents — Answer Key & Worked Solutions

Every question from the June 2025 Earth Science Regents exam, with the correct answer and a full step-by-step solution. Check your work, learn the method, then convert your raw score.

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These are real questions from the June 2025 Earth Science New York State Regents examination, published by NYSED. Worked solutions are written by RegentsLab.

Question 1 · 2 pts

The heliocentric model of the solar system shows the

Worked solution
$\text{Heliocentric} = \text{Sun-centered model}$ The heliocentric model places the Sun at the center with planets orbiting it at set distances.
Answer: location of the planets in relation to the Sun

The heliocentric model's defining feature is the arrangement of planets orbiting the Sun, showing their relative positions/distances from it.

Question 2 · 2 pts

The graph below shows the ocean tides at Battery Park in New York City from February 9 to February 15, 2020. The phases of the Moon for select dates are shown at the top of the graph (Full moon, Waning gibbous, Last quarter). Compared to tides that occur during other Moon phases, which conclusion about tides that occur during a full moon can be made from the graph?

earth question 2 figure
Worked solution
$\text{Full moon} \Rightarrow \text{Sun, Earth, Moon aligned}$ Alignment produces spring tides.
$\text{Spring tide range} > \text{neap tide range}$ Graph shows the highest high tides and lowest low tides occurring near the full moon dates, giving the greatest tidal range.
Answer: The tidal range is greater when there is a full moon.

Near the full moon the Sun and Moon align with Earth, producing spring tides with the largest difference between high and low tide (greatest tidal range), which is visible as the tallest peak-to-trough swing on the graph.

Question 3 · 2 pts

Evidence of Earth's rotation on its axis is provided by both the

Worked solution
$\text{Foucault pendulum: plane of swing appears to rotate}$ This apparent rotation is direct evidence Earth is spinning beneath the pendulum.
$\text{Coriolis effect: deflection of moving air/water}$ Caused by Earth's rotation, deflecting winds/currents right (NH) or left (SH).
Answer: Foucault pendulum and the Coriolis effect

Both the Foucault pendulum's apparent change in swing direction and the Coriolis deflection of moving fluids are direct consequences of, and thus evidence for, Earth's rotation on its axis.

Question 4 · 2 pts

At which New York State location is the observed altitude of Polaris approximately 42°?

Worked solution
$\text{Altitude of Polaris} = \text{observer's latitude}$ This is a key astronomy relationship.
$\text{Binghamton latitude} \approx 42^\circ N$ Of the listed NY cities, Binghamton sits closest to 42°N latitude.
Answer: Binghamton

The altitude of Polaris above the horizon equals the observer's latitude; Binghamton, NY lies at approximately 42° N latitude, matching the given altitude.

Question 5 · 2 pts

The diagram below represents a portion of Earth's latitude and longitude system. Letters A and B represent locations on Earth's surface. Point A is located at approximately 30° E longitude, 10° N latitude. Point B is located at approximately 30° W longitude, 20° S latitude. When the time at location A is 12 noon, what time is it at location B?

earth question 5 figure
Worked solution
$\Delta\lambda = 30^\circ E - (-30^\circ W) = 60^\circ$ Longitude difference between A and B.
$\Delta t = \frac{60^\circ}{15^\circ/\text{hr}} = 4\ \text{hours}$ Earth rotates 15° per hour.
$B \text{ is west of } A \Rightarrow \text{earlier local time}$ 12\text{ noon} - 4\text{ hr} = 8\text{ a.m.}
Answer: 8 a.m.

B is 60° of longitude west of A, and since Earth rotates 15° per hour, local time at B is 4 hours earlier than at A, making it 8 a.m. at B when it is 12 noon at A.

Question 6 · 2 pts

Orion is a constellation of stars that is visible in the evening sky in New York State from November through February. Orion is not visible the rest of the year because

Worked solution
$\text{Earth's orbital motion changes the night-side view of space}$ As Earth revolves, different constellations become visible in the night sky at different times of year.
Answer: Earth revolves around the Sun

Earth's revolution around the Sun changes which portion of the sky is visible at night throughout the year, explaining why Orion is seasonal rather than visible year-round.

Question 7 · 2 pts

The hydrosphere is a relatively thin layer of

Worked solution
$\text{Hydrosphere} = \text{all of Earth's water}$ Oceans, lakes, rivers, ice, and groundwater covering about 70% of Earth's surface.
Answer: water covering approximately 70% of Earth's surface

The hydrosphere consists of all water on Earth's surface, which covers approximately 70% of the planet's surface area.

Question 8 · 2 pts

Earth revolves around the Sun at a rate of approximately

Worked solution
$\frac{360^\circ}{365\ \text{days}} \approx 1^\circ/\text{day}$ Earth completes one full 360° orbit in about 365 days.
Answer: 1° per day

Earth's one full orbit (360°) around the Sun takes about 365 days, so it moves roughly 1° along its orbit per day.

Question 9 · 2 pts

The diagram below represents Earth's position relative to the Sun's rays on September 23. The arrow shows the Sun's direct rays striking the equator at solar noon. During the next six months, the angle of the Sun's rays striking the equator at solar noon will

earth question 9 figure
Worked solution
$\text{Sept 23 (equinox)}: \text{Sun directly overhead equator, angle} = 90^\circ$ Starting condition described in the diagram.
$\text{Sept} \rightarrow \text{Dec 21 (solstice)}: \text{direct rays shift to } 23.5^\circ S$ Sun's noon angle at the equator decreases from 90° toward 66.5°.
$\text{Dec 21} \rightarrow \text{Mar 21 (equinox)}: \text{direct rays shift back to equator}$ Angle increases back toward 90°.
Answer: decrease then increase

From the September equinox, the Sun's direct rays migrate south toward the December solstice (angle at the equator decreases), then migrate back toward the equator by the March equinox (angle increases again), so over the six months the angle decreases then increases.

Question 10 · 2 pts

Which type of unsaturated sediment will have the greatest permeability during a rainstorm?

Worked solution
$\text{Permeability} \propto \text{pore space connectivity}$ Rounded particles that are loosely packed leave the largest, most connected pore spaces.
$\text{Loosely packed} > \text{tightly packed for water flow}$ Tight packing and flattened/angular shapes reduce pore space and restrict water movement.
Answer: rounded and loosely packed

Rounded, loosely packed sediment has the largest connected pore spaces, allowing water to infiltrate most easily, giving it the greatest permeability.

Question 11 · 2 pts

The diagram below represents four different apparent paths of the Sun across the sky at four different locations. The paths are labeled A, B, C, and D, with angles of 48° and 24.5° marked at their peaks. Which line best represents the apparent path of the Sun across the sky on December 21 in New York State?

earth question 11 figure
Worked solution
$\text{Dec 21} = \text{winter solstice (NH)}$ Sun's noon altitude is lowest and the daytime arc is shortest of the year.
$\text{Lowest, shortest arc} \Rightarrow \text{path D}$ Among the four paths, D has the lowest maximum altitude and shortest arc across the sky.
Answer: D

On December 21 (winter solstice) in New York State the Sun follows its lowest, shortest daily arc across the sky, which corresponds to path D in the diagram.

Question 12 · 2 pts

Which table correctly indicates the locations of the polar front jet stream and subtropical jet stream near the time of the equinox? Table 1: Polar Front Jet Stream: 60° North and 60° South; Subtropical Jet Stream: 30° North and 30° South. Table 2: Polar Front Jet Stream: 30° North and 30° South; Subtropical Jet Stream: 60° North and 60° South. Table 3: Polar Front Jet Stream: 90° North and 90° South; Subtropical Jet Stream: 30° North and 30° South. Table 4: Polar Front Jet Stream: 90° North and 90° South; Subtropical Jet Stream: 60° North and 60° South.

Worked solution
$\text{Polar front jet} \approx 60^\circ N/S$ Located near the boundary of polar and mid-latitude air masses.
$\text{Subtropical jet} \approx 30^\circ N/S$ Located near the boundary of the Hadley and Ferrel cells.
Answer: Polar Front Jet Stream: 60° North and 60° South; Subtropical Jet Stream: 30° North and 30° South

Near the equinox, the polar front jet stream is located near 60° N/S latitude and the subtropical jet stream near 30° N/S latitude, matching table 1.

Question 13 · 2 pts

The station model below represents some weather conditions at Syracuse, New York, showing a temperature of 86°F, a dewpoint of 80°F, a mostly-shaded (nearly overcast) sky symbol, and wind barbs extending toward the lower right (from the east) with two full barbs. What is the best description of the weather at Syracuse?

earth question 13 figure
Worked solution
$T = 86^\circ F,\ T_d = 80^\circ F$ Small temperature-dewpoint spread (6°F) indicates high relative humidity (humid conditions).
$\text{Wind barb shaft points from the direction wind originates}$ The shaft extending toward the east indicates wind is blowing from the east.
Answer: hot and humid with winds from the east

A small spread between temperature (86°F) and dewpoint (80°F) indicates humid air, and the wind barb's shaft points to the east, showing the wind is coming from the east, so the weather is hot and humid with easterly winds.

Question 14 · 2 pts

Which air mass is characterized by high relative humidity and low air temperature?

Worked solution
$\text{maritime} \Rightarrow \text{moist (high humidity)}$ Forms over ocean water.
$\text{polar} \Rightarrow \text{cold (low temperature)}$ Forms at high latitudes.
Answer: maritime polar

Maritime air masses form over water and are moist (high humidity), while polar air masses form at high latitudes and are cold, so a maritime polar air mass is both cold and humid.

Question 15 · 2 pts

The incomplete flow chart below represents heat sources that provide energy for Earth's systems. The types of heat sources, labeled A, B, and C, have been left blank, branching from 'Internal heat sources' (A and B) and 'External heat source' (C) beneath 'Earth's Systems: Driven by'. Which flow chart correctly identifies the types of heat sources for A, B, and C?

earth question 15 figure
Worked solution
$\text{Internal heat} = \text{radioactive decay} + \text{residual heat from formation}$ Both originate from within Earth.
$\text{External heat} = \text{solar energy}$ Comes from outside Earth (the Sun).
Answer: Internal heat sources: radioactive decay, residual heat from Earth's formation; External heat source: solar energy

Earth's internal heat sources are radioactive decay and residual heat left over from Earth's formation, while the external heat source driving Earth's systems is solar energy from the Sun.

Question 16 · 2 pts

A visible satellite image of the eastern United States is shown below. Visible satellite images resemble black and white photographs because clouds reflect sunlight and appear white, while land and water appear in shades of gray or black. Which weather variable can be most accurately forecast using this satellite image?

earth question 16 figure
Worked solution
$\text{Cloud cover (white areas)} \Rightarrow \text{likely precipitation locations}$ Visible imagery shows cloud extent/location, which correlates with where precipitation is occurring or likely.
Answer: areas of precipitation

Because clouds appear white in visible satellite imagery, the image directly shows where cloud cover (and therefore likely precipitation) is located, but it cannot reveal temperature, wind speed, or precipitation type.

Question 17 · 2 pts

The cross sections below show widely separated outcrops labeled 1, 2, and 3. The rock layers have not been overturned. Letters W, X, Y, and Z represent fossils in some of the layers. Outcrop 1 (bottom to top): X, then a layer with W near the top. Outcrop 2 (bottom to top): Z, then a layer with Y above it. Outcrop 3 (bottom to top): W, then a layer with Z above it. Which column represents the correct sequence of fossils based on the correlation of the three outcrops?

earth question 17 figure
Worked solution
$\text{Outcrop 1}: X \text{ (bottom)} \rightarrow W \text{ (top)}$ Gives relative order X before W.
$\text{Outcrop 3}: W \text{ (bottom)} \rightarrow Z \text{ (top)}$ Gives relative order W before Z, linking to outcrop 1 via shared fossil W.
$\text{Outcrop 2}: Z \text{ (bottom)} \rightarrow Y \text{ (top)}$ Gives relative order Z before Y, linking via shared fossil Z.
$\text{Combined sequence (oldest to youngest)}: X, W, Z, Y$ Correlating all three outcrops by overlapping fossils in stratigraphic order.
Answer: Column (bottom to top): X, W, Z, Y

By using the overlapping fossils (W links outcrops 1 and 3; Z links outcrops 3 and 2) and the principle of superposition, the correlated sequence from oldest (bottom) to youngest (top) is X, W, Z, Y.

Question 18 · 2 pts

Which land surface absorbs the greatest amount of insolation?

Worked solution
$\text{Dark surfaces} \Rightarrow \text{low albedo} \Rightarrow \text{more absorption}$ Dark colors absorb more radiation than light (reflective) colors.
$\text{Rough textures} \Rightarrow \text{more surface area, less reflection}$ Rough surfaces scatter and trap more incoming radiation than smooth surfaces.
Answer: dark color and rough texture

Dark-colored, rough-textured surfaces have the lowest albedo and the greatest surface area for trapping radiation, so they absorb the most insolation.

Question 19 · 2 pts

During which era of Earth's geologic history did oceanic oxygen begin to enter Earth's atmosphere?

Worked solution
$\text{Photosynthetic cyanobacteria} \Rightarrow O_2 \text{ release}$ Oxygen released by early photosynthetic organisms first accumulated in oceans, then began entering the atmosphere.
$\text{Great Oxidation Event} \approx \text{Early Proterozoic}$ This event, marking oxygen's entry into the atmosphere, is recorded on the Geologic History reference table in the Early Proterozoic Era.
Answer: Early Proterozoic Era

According to the Geologic History of New York reference table, oceanic oxygen began entering Earth's atmosphere during the Early Proterozoic Era, as photosynthetic life increased atmospheric oxygen levels.

Question 20 · 2 pts

When did humans appear on Earth?

Worked solution
$\text{Humans, mastodonts, mammoths} \Rightarrow \text{Cenozoic (Quaternary Period)}$ According to the Geologic History reference table, these life forms' time spans overlap in the late Cenozoic Era.
Answer: during the same time as mastodonts and mammoths

The Geologic History reference table shows that the earliest humans appeared during the same time span as mastodonts and mammoths, in the late Cenozoic Era.

Question 21 · 2 pts

If a rock contained 200 grams of the radioactive isotope potassium-40 ($^{40}K$) when it was formed, but now contains only 25 grams of potassium-40 ($^{40}K$), how many years ago did the rock form?

Worked solution
$200 \to 100 \to 50 \to 25\ \text{grams}$ Each arrow represents one half-life of potassium-40.
$\text{Number of half-lives} = 3$ It took 3 half-lives to reduce 200 g to 25 g.
$3 \times (1.3 \times 10^9\ \text{yr}) = 3.9 \times 10^9\ \text{yr}$ Using the half-life of potassium-40 from the reference tables (1.3 billion years).
Answer: $3.9 \times 10^9$ years

Going from 200 g to 25 g of potassium-40 requires 3 half-lives (200→100→50→25); multiplying by potassium-40's half-life of 1.3 × 10^9 years gives 3.9 × 10^9 years since the rock formed.

Question 22 · 2 pts

The Alleghenian and Acadian orogenies were caused by which geologic process?

Worked solution
$\text{Orogeny} = \text{mountain-building event}$ The Acadian and Alleghenian orogenies built the ancestral Appalachian Mountains.
$\text{Continental collision} \Rightarrow \text{crustal compression/uplift}$ These orogenies resulted from the collision of landmasses (converging plates) during the assembly of Pangaea.
Answer: collision of landmasses

The Acadian and Alleghenian orogenies were mountain-building events caused by the collision of landmasses (continental plates converging) as ancient continents came together.

Question 23 · 2 pts

The continents of Africa and South America were inferred to be two separate continents

Worked solution
$\text{Use the Inferred Positions of Earth's Landmasses diagrams in the ESRT}$
$\text{The panel showing Africa and South America as separate, distinct continents is dated at about 65 million years ago}$
$\text{Of the choices given, 59 million years ago is the correct match}$
Answer: 59 million years ago

The ESRT landmass reconstruction panels show Pangea breaking apart over time; Africa and South America appear as clearly separated continents only in the youngest (most recent) reconstruction, dated at roughly 59 million years ago.

Question 24 · 2 pts

Which surface feature was produced by crustal movements at a divergent plate boundary?

Worked solution
$\text{San Andreas Fault forms at a transform plate boundary}$
$\text{Peru-Chile Trench forms at a convergent (subduction) boundary}$
$\text{A mid-ocean ridge such as the Southeast Indian Ridge forms where plates pull apart (divergent boundary)}$
$\text{The Tasman Hot Spot is not associated with a plate boundary at all}$
Answer: Southeast Indian Ridge

Mid-ocean ridges, like the Southeast Indian Ridge, form where two plates diverge and new oceanic crust is created, making it the correct choice for a divergent boundary feature.

Question 25 · 2 pts

Which Earth layer has a density similar to the density of Mercury?

Worked solution
$\text{Mercury's average density is about } 5.4\ \text{g/cm}^3$
$\text{From the Earth's Interior diagram in the ESRT, the stiffer mantle has a density range that includes values near } 5\ \text{g/cm}^3$
$\text{Oceanic crust (}\approx 3.0\ \text{g/cm}^3\text{) is too low, while the outer and inner core densities (}10\text{-}13\ \text{g/cm}^3\text{) are too high}$
Answer: stiffer mantle

Comparing Mercury's density (about 5.4 g/cm^3) to the density ranges given for Earth's layers on the Earth's Interior diagram, the stiffer mantle is the closest match.

Question 26 · 2 pts

Which factor is primarily responsible for the development of the stream drainage patterns in New York State?

Worked solution
$\text{Drainage patterns (dendritic, trellis, radial, etc.) form in response to the underlying rock structure}$
$\text{Bedrock structure, such as jointing, folding, and rock type arrangement, controls the paths streams follow}$
Answer: bedrock structure

Stream drainage patterns are shaped by the structural arrangement of the underlying bedrock (folds, faults, joints, rock resistance), not by the age or fossil content of the rock.

Question 27 · 2 pts

Which processes result in the formation of soil?

Worked solution
$\text{Soil forms from the physical and chemical weathering of bedrock combined with organic matter from living organisms}$
Answer: biological activity and the weathering of rocks

Soil is produced through weathering of rock material along with contributions of organic matter from plants, animals, and microorganisms (biological activity).

Question 28 · 2 pts

The table below shows the densities of four mineral samples of equal size and shape transported in a stream. As this stream flows into a lake, which mineral sample would most likely be deposited first?

earth question 28 figure
Worked solution
$\text{As stream velocity decreases entering the lake, the densest (heaviest) particles settle out first}$
$\text{Pyrite has the greatest density, } 5.0\ \text{g/cm}^3\text{, among the four minerals listed}$
Answer: pyrite

Because all four samples are equal in size and shape, the mineral with the greatest density (pyrite) requires the least amount of stream energy to remain suspended and will settle out first as the stream slows entering the lake.

Question 29 · 2 pts

Hematite and magnetite are mined as ores because they contain the element

Worked solution
$\text{Hematite (Fe}_2\text{O}_3\text{) and magnetite (Fe}_3\text{O}_4\text{) are both iron oxide minerals}$
Answer: iron

Hematite and magnetite are the two most important iron ore minerals; both are iron oxides mined primarily for their iron content.

Question 30 · 2 pts

The cross section below represents a portion of Earth's crust. The basalt intrusion contains several inclusions. The relative age of the limestone inclusion is

earth question 30 figure
Worked solution
$\text{An inclusion within an igneous intrusion must be older than the intrusion itself (it was existing rock engulfed by the magma)}$
$\text{The limestone inclusion is a fragment of a limestone layer located below the siltstone layer in the cross section, so it also predates (is older than) the siltstone layer}$
Answer: older than the basalt and older than the siltstone layer

By the law of inclusions, a rock fragment found inside an igneous rock (the basalt) must be older than that igneous rock; the cross section also shows the limestone layer lying beneath (and therefore older than) the siltstone layer.

Question 31 · 2 pts

The block diagram below represents the magnetic orientation of igneous bedrock on the seafloor on the western and eastern sides of a mid-ocean ridge. The letters A, B, C, D, and X identify locations of specific bands of magnetic orientation. Which location is the same age as location X?

earth question 31 figure
Worked solution
$\text{Seafloor spreading produces magnetic bands that are symmetric on either side of a mid-ocean ridge}$
$\text{Bands at equal distances from the ridge center on opposite sides formed at the same time and are the same age}$
$\text{Matching X's distance and band position from the ridge center to the corresponding band on the eastern side gives location D}$
Answer: D

Because new crust forms symmetrically at a mid-ocean ridge and spreads outward in both directions, a band at a given distance from the ridge on one side is the same age as the band at the same distance on the other side; this pairs X with D.

Question 32 · 2 pts

The photograph below shows an escarpment feature formed by uplift and erosion. An escarpment is best described as a

earth question 32 figure
Worked solution
$\text{An escarpment is a long, steep slope or cliff separating two relatively level land surfaces of differing elevation}$
Answer: steep, rocky cliff

An escarpment is defined as a steep, rocky cliff or slope, typically formed by uplift followed by differential erosion.

Question 33 · 2 pts

The photograph below shows parallel scratches on the surface of a rock. Which erosional agent most likely produced these parallel scratches?

earth question 33 figure
Worked solution
$\text{Glacial striations are parallel scratches and grooves cut into bedrock as a moving glacier drags embedded rock fragments across the surface}$
Answer: glacier

Long, straight, parallel scratches (striations) on bedrock are a classic sign of glacial erosion, produced as rock debris embedded in the base of a moving glacier scrapes across the surface.

Question 34 · 2 pts

The picture below shows a sample of the metamorphic rock hornfels. Hornfels is commonly formed when existing rock is changed due to

earth question 34 figure
Worked solution
$\text{Hornfels is a fine-grained, non-foliated metamorphic rock}$
$\text{It forms through contact metamorphism, where heat from rising magma bakes surrounding rock}$
Answer: contact with rising magma from tectonic activity

Hornfels forms by contact metamorphism, when heat from an intruding magma body alters (bakes) the surrounding rock, producing a hard, non-foliated texture.

Question 35 · 2 pts

The diagram below represents a stream entering a lake. Letters A, B, C, and D represent locations in the stream. At which two locations in the stream will the greatest amount of deposition be occurring?

earth question 35 figure
Worked solution
$\text{Stream velocity decreases sharply as a stream approaches and enters a standing body of water such as a lake}$
$\text{Locations C and D are nearest the mouth of the stream where it enters the lake, so velocity (and thus carrying capacity) is lowest there}$
$\text{Lower velocity means the greatest amount of sediment deposition occurs at C and D}$
Answer: C and D

As a meandering stream nears its mouth (where it enters the lake), its velocity decreases the most, so the greatest deposition occurs at the locations closest to the lake, C and D.

Question 36 · 2 pts

Base your answer on the diagram representing Earth orbiting the Sun with four positions A, B, C, and D labeled, letter N representing the North Pole, distances shown for aphelion (152 million km) and perihelion (147 million km), arrows indicating direction of orbital movement, and letter X representing a latitude on Earth. Approximately how many days does Earth take to move from position A to position D?

earth question 36 figure
Worked solution
$\text{The four labeled positions A, B, C, D divide Earth's roughly 365-day orbit into quarters (about 91 days each)}$
$\text{Following the direction of orbital motion shown by the arrows, Earth travels from A through B and C before reaching D, covering three of the four quarter-orbit segments}$
$3 \times 91\ \text{days} \approx 274\ \text{days}$
Answer: 274 days

Since the diagram's arrows show Earth's motion carrying it from A around through B and C before arriving at D, this path covers three-quarters of the full orbit, or about 274 days.

Question 37 · 2 pts

Base your answer on the diagram representing Earth orbiting the Sun with four positions A, B, C, and D labeled, letter N representing the North Pole, distances shown for aphelion and perihelion, and letter X representing a latitude on Earth at position A. Which latitude on Earth is represented by location X?

earth question 37 figure
Worked solution
$\text{At position A, the diagram shows the Northern Hemisphere tilted away from the Sun (winter solstice conditions), placing X within the region of continuous night}$
$\text{The latitude marking the boundary of continuous night during the winter solstice in the Northern Hemisphere is the Arctic Circle}$
Answer: Arctic Circle

Location X is drawn at the high northern latitude experiencing continuous darkness at the position corresponding to the December solstice, identifying it as the Arctic Circle.

Question 38 · 2 pts

If the tilt of Earth's axis were increased from 23.5° to 31°, the Northern Hemisphere summer would become

Worked solution
$\text{A greater axial tilt increases the angle of insolation (Sun's rays being more direct) at a hemisphere during its summer, increasing summer heating}$
$\text{A greater tilt also increases the angle of insolation being less direct during that hemisphere's winter, decreasing winter heating}$
$\text{Thus, greater tilt produces more extreme seasons: warmer summers and cooler winters}$
Answer: warmer and winter would become cooler

Increasing Earth's axial tilt increases the seasonal extremes: summers become warmer (more direct sunlight, longer days) and winters become cooler (less direct sunlight, shorter days) in the Northern Hemisphere.

Question 39 · 2 pts

Base your answer on the passage and map about the Dead Sea. The Dead Sea is the lowest point on the surface of Earth. It is a lake at the mouth of the Jordan River, with water 10 times saltier than the ocean. Small amounts of dissolved minerals are transported into the Dead Sea, and over thousands of years these minerals are left behind when the water evaporates. Recent demand for water has decreased the lake's water level from 1296 feet below sea level in 1896 to 1412 feet below sea level in 2016, so the Jordan River's fresh water must flow farther and dissolves layers of minerals previously deposited around the Dead Sea. Which mineral is most commonly found on the shores of the Dead Sea?

earth question 39 figure
Worked solution
$\text{The Dead Sea is extremely saline, and evaporation of this salty water precipitates evaporite minerals}$
$\text{Halite (rock salt, NaCl) is the common evaporite mineral left behind as very salty water evaporates}$
Answer: halite

As the highly saline water of the Dead Sea evaporates, dissolved sodium chloride precipitates out as halite, making it the most common mineral found along its shores.

Question 40 · 2 pts

The map below shows the tectonic plate boundary located at the Dead Sea, between the Sinai Sub-plate and the Arabian Plate, extending from the Red Sea north past the Dead Sea. Arrows along the boundary near the Dead Sea point in opposite directions (one plate moving toward the viewer's lower position, the other toward the upper position), parallel to the boundary line. Which type of tectonic plate boundary is found where the Dead Sea is located?

earth question 40 figure
Worked solution
$\text{The arrows on the map show the Sinai Sub-plate and Arabian Plate sliding past each other in opposite directions along the same fault line}$
$\text{Plates sliding horizontally past one another, neither colliding nor separating, define a transform plate boundary}$
Answer: transform

The opposing arrows parallel to the plate boundary indicate the two plates are sliding horizontally past each other, which is the defining characteristic of a transform plate boundary (like the Dead Sea Transform fault).

Question 41 · 2 pts

Base your answer on the seismogram and data table for an earthquake recorded at a seismic monitoring station. The seismogram shows a P-wave arrival and an S-wave arrival between time marks 2:28:00 and 2:36:00. The data table states: Time of P-wave arrival = 02:30:00 p.m., Time of S-wave arrival = 02:34:00 p.m., Distance to epicenter = 2600 km. At what time did this earthquake occur?

earth question 41 figure
Worked solution
$\text{S-P interval} = 02{:}34{:}00 - 02{:}30{:}00 = 4\ \text{minutes}$
$\text{This confirms a distance to the epicenter of about 2600 km, consistent with the data table}$
$\text{Using the Earthquake P-wave and S-wave Travel Time graph in the ESRT, the P-wave takes about 5 minutes to travel 2600 km}$
$\text{Origin time} = 02{:}30{:}00 - 5\ \text{minutes} = 02{:}25{:}00\ \text{p.m.}$
Answer: 02:25:00 p.m.

Using the Earthquake Travel Time graph, a P-wave travels about 2600 km in roughly 5 minutes, so subtracting that travel time from the P-wave arrival time (02:30:00 p.m.) gives an origin time of about 02:25:00 p.m.

Question 42 · 2 pts

Four seismograms (1 through 4) are shown, each spanning 2:28:00 to 2:36:00 and each showing a P-wave arrival and an S-wave arrival at different times/separations. Which seismogram was recorded closest to the epicenter of this earthquake?

earth question 42 figure
Worked solution
$\text{The distance to the epicenter is proportional to the S-P time interval: a smaller S-P interval means a closer epicenter}$
$\text{Comparing the four seismograms, seismogram (1) has the P-wave and S-wave arrivals closest together in time}$
Answer: seismogram (1)

A seismic monitoring station closer to the epicenter records a shorter time gap between the P-wave and S-wave arrivals; seismogram (1) shows the smallest S-P interval of the four, indicating it is closest to the epicenter.

Question 43 · 2 pts

Base your answer on the graph 'Evolution of Brachiopods,' which indicates changes in the number of four different brachiopod groups (Orthida, Rhynchonellida, Spiriferida, Terebratulida) from the early Cambrian to the present, with bar width indicating the relative number of types within each group across geologic time periods (Cambrian, Ordovician, Silurian, Devonian, Carboniferous, Permian, Triassic, Jurassic, Cretaceous, Paleogene and Neogene, Quaternary). What does this graph indicate about the history of the Orthida group?

earth question 43 figure
Worked solution
$\text{The Orthida bar in the graph widens (many types) during the Ordovician-Silurian, then narrows and ends before reaching the present-day column}$
$\text{A bar that ends before the present indicates the group became extinct, even though many types existed at its peak}$
Answer: Many types have lived in the past and are now extinct.

The graph shows the Orthida group's bar widening (many types existing) earlier in geologic history but ending well before the present day, showing that although many types once lived, the entire group is now extinct.

Question 44 · 2 pts

Base your answer on the 'Evolution of Brachiopods' graph described above. Which two other fossil groups found in New York State first appeared on Earth during the same geologic time period that the Orthida Brachiopod group first appeared?

earth question 44 figure
Worked solution
$\text{The graph shows the Orthida group first appearing in the Cambrian period}$
$\text{From the Geologic History of New York State chart in the ESRT, trilobites and gastropods both first appeared during the Cambrian period}$
$\text{Eurypterids first appeared later (Ordovician), and ammonoids first appeared even later (Devonian), so they do not match}$
Answer: trilobites and gastropods

Since the Orthida brachiopods first appear in the Cambrian on the graph, matching this with the ESRT geologic history chart shows trilobites and gastropods are the NY State fossil groups that also first appeared in the Cambrian.

Question 45 · 2 pts

Base your answers to questions 43 through 45 on the graph below and on your knowledge of Earth science. The graph indicates changes in the number of four different brachiopod groups from the early Cambrian to the present. A picture of a representative member of each group is shown in the left column. The width of each bar indicates the relative number of different types of brachiopods within each group. Which brachiopod group had the greatest number of types of organisms existing at the time of existence of the New York State index fossil Platyceras?

earth question 45 figure
Worked solution
$\text{Platyceras is a Devonian index fossil (per the ESRT)}$
$\text{Compare bar widths of all four brachiopod groups during the Devonian period}$
$\text{Spiriferida has the widest bar (greatest number of types) during the Devonian}$
Answer: Spiriferida

Platyceras is a Devonian-age index fossil. Reading the graph at the Devonian column, the Spiriferida bar is widest, indicating it had the greatest number of types at that time.

Question 46 · 2 pts

Base your answers to questions 46 through 48 on the contour map below and on your knowledge of Earth science. The contour map shows elevations in meters on the Big Island of Hawaii. The elevation of Mauna Loa, a volcanic mountain, is indicated. The large arrow represents the direction of prevailing winds. Compared to Kailua-Kona, the amount of rainfall received at Hilo is

earth question 46 figure
Worked solution
$\text{Prevailing winds blow from the Pacific Ocean toward Hilo (windward side)}$
$\text{Ocean winds carry more moisture than winds that have crossed the island (leeward, Kailua-Kona)}$
$\text{Windward side receives more rainfall due to orographic lifting of moist air}$
Answer: greater due to Hilo receiving winds containing more moisture

Hilo is on the windward side facing the ocean, so it receives moisture-laden winds directly off the Pacific, causing greater rainfall than Kailua-Kona on the leeward (drier) side.

Question 47 · 2 pts

After visible light is absorbed by the land surfaces of the Big Island of Hawaii, which form of long-wave electromagnetic energy is radiated?

Worked solution
$\text{Earth's surfaces absorb short-wave visible light from the Sun}$
$\text{Absorbed energy is re-radiated as long-wave (lower energy, longer wavelength) radiation}$
$\text{Infrared is the long-wave form of electromagnetic energy radiated by Earth's surface}$
Answer: infrared

Earth's surface absorbs short-wave visible light and re-emits it as long-wave infrared radiation, consistent with the electromagnetic spectrum on the ESRT.

Question 48 · 2 pts

Compared to Puna, Mauna Loa has a cooler climate because Mauna Loa

earth question 48 figure
Worked solution
$\text{Temperature decreases with increasing elevation (average lapse rate)}$
$\text{Mauna Loa (4169 m) is at a much higher elevation than Puna, which is near sea level}$
$\text{Higher elevation results in a cooler climate}$
Answer: has a higher elevation

Mauna Loa's summit is much higher in elevation than Puna, and temperature decreases with altitude, making its climate cooler.

Question 49 · 2 pts

Base your answers to questions 49 and 50 on the block diagram below and on your knowledge of Earth science. The block diagram shows a portion of Earth's crust and some processes within the water cycle. Letters A, B, C, and D represent different areas and zones on the diagram. Letter X represents a water cycle process. An increase in yearly precipitation would most likely cause

earth question 49 figure
Worked solution
$\text{More precipitation means more water infiltrates and percolates downward}$
$\text{Increased water reaching the zone of saturation (D) raises the water table}$
$\text{Erosion at A and infiltration at B would increase, not decrease, with more precipitation}$
Answer: increased groundwater in zone $D$, raising the water table

More precipitation increases infiltration and adds water to the zone of saturation (D), which raises the water table.

Question 50 · 2 pts

Process X, labeled in the diagram, represents

earth question 50 figure
Worked solution
$\text{Process X shows wavy upward arrows rising from vegetation/ground toward clouds}$
$\text{This represents water vapor moving from plants and soil into the atmosphere}$
$\text{This process is transpiration (combined with evaporation, i.e., evapotranspiration)}$
Answer: transpiration

The upward wavy arrows from the land surface (near vegetation) toward the clouds represent transpiration, the release of water vapor from plants into the atmosphere.

Question 51 · 1 pt · constructed response

Base your answers to questions 51 through 54 on the passage and diagram below and on your knowledge of Earth science. The diagram represents a developing system indicating the frost line around a protostar (early star). Planet Formation and the Frost Line Our solar system formed in an immense region of gases with metallic and rocky debris known as a nebula. The frost line marks a temperature boundary between the higher temperature region near the protostar (which later became the Sun) and the lower temperature outer region. Temperature determined the types of materials that began to form the early planets. Inside the frost line, closer to the protostar, metallic and rocky materials condensed and solidified into rocky planets. Outside of the frost line, lighter elements and gases condensed, with some solidifying, making the size of these planets larger. The four planets that formed inside of the frost line are referred to as the terrestrial planets. The four planets that formed outside of the frost line are referred to as the Jovian planets. On the graph in your answer booklet, draw a line to represent the general relationship between the distance from a protostar and the temperature in the nebula.

Model answer: A line that starts high (high temperature) close to the protostar (at distance = 0) and decreases continuously (curves or slopes downward) as distance from the protostar increases, showing an inverse relationship between distance and temperature.
Worked solution
$\text{Temperature is highest closest to the protostar (heat source)}$
$\text{As distance from the protostar increases, temperature decreases}$
$\text{Draw a downward-sloping (or downward-curving) line from high temperature at low distance to low temperature at high distance}$
Answer: A line that starts high (high temperature) close to the protostar (at distance = 0) and decreases continuously (curves or slopes downward) as distance from the protostar increases, showing an inverse relationship between distance and temperature.

Since the protostar is the heat source, temperature in the nebula is inversely related to distance from it, so the graphed line should start high near the protostar and continuously decrease with increasing distance.

Question 52 · 1 pt · constructed response

Identify the names of the two planets that formed directly on either side of the frost line.

Model answer: Mars and Jupiter
Worked solution
$\text{The frost line lies between the terrestrial and Jovian planet zones}$
$\text{The terrestrial planets are Mercury, Venus, Earth, Mars (innermost to outermost)}$
$\text{The Jovian planets are Jupiter, Saturn, Uranus, Neptune (innermost to outermost)}$
$\text{The planet just inside the frost line is Mars; the planet just outside is Jupiter}$
Answer: Mars and Jupiter

Mars is the outermost terrestrial (rocky) planet, located just inside the frost line, and Jupiter is the innermost Jovian (gas) planet, located just outside the frost line.

Question 53 · 1 pt · constructed response

Since the origin of our Solar System, the Sun has evolved from a protostar to its current early stage position in the main sequence. Identify the star classification of our Sun when it will be in the late stage of its development.

Model answer: White dwarf
Worked solution
$\text{The Sun is currently a main sequence star (G-type)}$
$\text{Per the ESRT star evolution diagram, a main sequence star like the Sun evolves into a red giant, then sheds outer layers}$
$\text{The remaining core becomes a white dwarf, the late-stage classification for a star of the Sun's mass}$
Answer: White dwarf

According to the Star Evolution diagram in the ESRT, a Sun-mass main sequence star eventually becomes a red giant and then collapses into a white dwarf, which is its late-stage classification.

Question 54 · 1 pt · constructed response

Identify the nuclear process that produces energy when a protostar becomes a star like our Sun.

Model answer: Nuclear fusion (fusion of hydrogen into helium)
Worked solution
$\text{A protostar contracts and heats up under gravity until core temperature/pressure is high enough}$
$\text{Hydrogen nuclei fuse together to form helium, releasing energy}$
$\text{This nuclear fusion process marks the star's entry into the main sequence}$
Answer: Nuclear fusion (fusion of hydrogen into helium)

When a protostar's core becomes hot and dense enough, nuclear fusion of hydrogen into helium begins, producing the energy that defines it as a main sequence star.

Question 55 · 1 pt · constructed response

Base your answers to questions 55 and 56 on the geologic cross section below and on your knowledge of Earth science. Numbers 1 through 5 represent rock units. Line AB represents a fault. Lines X and Y represent unconformities. The rock layers have not been overturned. Identify one metamorphic rock that was most likely formed in the zone of contact metamorphism between rock unit 4 and the intrusion.

earth question 55 figure
Model answer: Hornfels (any correct contact metamorphic rock such as hornfels is acceptable)
Worked solution
$\text{Contact metamorphism occurs when hot igneous intrusions bake surrounding rock}$
$\text{This process typically produces a fine-grained, non-foliated metamorphic rock}$
$\text{Hornfels is the classic contact metamorphic rock formed by this baking process}$
Answer: Hornfels (any correct contact metamorphic rock such as hornfels is acceptable)

Contact metamorphism from an igneous intrusion heating surrounding rock typically produces hornfels, a fine-grained, nonfoliated metamorphic rock.

Question 56 · 1 pt · constructed response

Describe one piece of evidence shown in the cross section that indicates layer 3 has undergone crustal movement.

earth question 56 figure
Model answer: Layer 3 is folded/bent (or is offset/displaced by fault AB), which indicates it was subjected to crustal movement (compressional stress causing folding, or faulting causing displacement).
Worked solution
$\text{Examine the shape and position of rock unit 3 in the cross section}$
$\text{Unit 3 appears folded (bent from its original horizontal, flat-lying position)}$
$\text{Folding of originally horizontal sedimentary layers is evidence of crustal movement (compression)}$
Answer: Layer 3 is folded/bent (or is offset/displaced by fault AB), which indicates it was subjected to crustal movement (compressional stress causing folding, or faulting causing displacement).

Layer 3 is shown folded rather than lying flat and horizontal as sediments originally deposit, which is direct evidence that crustal (tectonic) forces bent the layer after it formed. Alternatively, its offset across fault AB is also acceptable evidence of crustal movement.

Question 57 · 1 pt · constructed response

Base your answers to questions 57 through 59 on the weather map below and on your knowledge of Earth science. The weather map shows a high-pressure system (H) and low-pressure system (L). Two different fronts associated with this low-pressure system are indicated. Isobars are in millibars (mb). Points A through D represent locations on Earth's surface. Identify the lettered location on the map, A, B, C, or D, that has the greatest wind speed. Describe one piece of evidence on the map that indicates that this location has the greatest wind speed.

earth question 57 figure
Model answer: Location A; the isobars are most closely spaced (packed tightly together) near point A, indicating the greatest pressure gradient and therefore the greatest wind speed.
Worked solution
$\text{Wind speed is directly related to the pressure gradient, shown by isobar spacing}$
$\text{Closely spaced isobars indicate a steep pressure gradient and higher wind speed}$
$\text{Point A is located near the low-pressure center where isobars 992-1008 mb are tightly packed}$
$\text{Therefore location A has the greatest wind speed}$
Answer: Location A; the isobars are most closely spaced (packed tightly together) near point A, indicating the greatest pressure gradient and therefore the greatest wind speed.

Wind speed correlates with how closely isobars are spaced; point A sits where isobars are packed closest together near the low-pressure center, indicating the steepest pressure gradient and strongest winds.

Question 58 · 1 pt · constructed response

In your answer booklet, circle one characteristic in each row that describes the general surface wind circulation pattern associated with the high-pressure system.

earth question 58 figure
Model answer: Clockwise and outward (diverging) from the center
Worked solution
$\text{In the Northern Hemisphere, high-pressure systems have clockwise surface wind circulation}$
$\text{Winds flow outward from the center of a high-pressure system (diverging)}$
$\text{Circle 'clockwise' in the row for rotation and 'outward' (diverging) in the row for direction}$
Answer: Clockwise and outward (diverging) from the center

Surface winds around a Northern Hemisphere high-pressure system circulate clockwise and spiral outward (diverge) from the center due to the Coriolis effect and pressure gradient force.

Question 59 · 1 pt · constructed response

Convert the air pressure of the lowest isobar shown on the map from millibars (mb) to inches of mercury (in of Hg).

earth question 59 figure
Model answer: 29.29 in of Hg (approximately)
Worked solution
$\text{The lowest isobar shown on the map is 992 mb (innermost isobar around the low-pressure center)}$
$\text{Using the ESRT conversion: } 1013.2\ \text{mb} = 29.92\ \text{in of Hg}$
$992\ \text{mb} \times \frac{29.92\ \text{in of Hg}}{1013.2\ \text{mb}} \approx 29.29\ \text{in of Hg}$
Answer: 29.29 in of Hg (approximately)

The lowest isobar on the map is 992 mb; converting using the standard ratio of 1013.2 mb = 29.92 in of Hg gives approximately 29.29 in of Hg.

Question 60 · 1 pt · constructed response

Base your answers to questions 60 and 61 on the maps below and on your knowledge of Earth science. Map A shows warm and cold areas of the Pacific Ocean under normal conditions. Map B shows areas of warmer water under El Nino conditions. Identify the two warm ocean currents that transport water from South America to Australia under normal conditions.

earth question 60 figure
Model answer: The South Equatorial Current and the North Equatorial Current
Worked solution
$\text{Under normal conditions, trade winds push warm surface water westward along the equator}$
$\text{This warm water flow from South America toward Australia/Asia occurs via equatorial currents}$
$\text{Per the ESRT ocean current map, these are the North Equatorial Current and South Equatorial Current}$
Answer: The South Equatorial Current and the North Equatorial Current

According to the ESRT surface ocean currents map, the North Equatorial Current and South Equatorial Current both flow westward across the Pacific, carrying warm water from near South America toward Australia and Asia under normal conditions.

Question 61 · 1 pt · constructed response

Describe how the relative air temperature and relative amount of precipitation along the west coast of South America are affected by an El Nino event.

earth question 61 figure
Model answer: Both air temperature and precipitation increase (become higher/greater) along the west coast of South America during an El Nino event.
Worked solution
$\text{During El Nino, warm water that is normally in the western Pacific shifts eastward to South America's coast}$
$\text{Warmer coastal water heats the overlying air, increasing air temperature}$
$\text{Warmer air holds more moisture and rises more readily, increasing precipitation along the coast}$
Answer: Both air temperature and precipitation increase (become higher/greater) along the west coast of South America during an El Nino event.

El Nino replaces the normally cold coastal water off South America with warm water, which raises air temperatures and increases precipitation along that coast due to greater evaporation and convection.

Question 62 · 1 pt · constructed response

Base your answers to questions 62 through 65 on the flowchart below and on your knowledge of Earth science. The flow chart shows a scheme for classifying rocks. The circled letters A, B, C, and D indicate parts of the chart that have not been completed. Identify two processes necessary to produce the class of rock represented by letter A.

earth question 62 figure
Model answer: Cooling and solidification (crystallization) of molten magma or lava
Worked solution
$\text{Letter A is the rock class with Intrusive/Extrusive types and Basalt as an extrusive example}$
$\text{This identifies A as the Igneous rock class}$
$\text{Igneous rocks form through melting (to produce magma/lava) and cooling/solidification (crystallization)}$
Answer: Cooling and solidification (crystallization) of molten magma or lava

Since Basalt (extrusive) is an example under class A, A must be Igneous rock, which forms through the processes of melting and subsequent cooling/solidification (crystallization) of magma or lava.

Question 63 · 1 pt · constructed response

State the type of sedimentary rock represented by letter B.

earth question 63 figure
Model answer: Clastic (fragmental) sedimentary rock
Worked solution
$\text{Sedimentary rock types shown are B, Crystalline, and Bioclastic}$
$\text{Crystalline forms from precipitated minerals (e.g., rock gypsum) and Bioclastic from organic material (e.g., bituminous coal)}$
$\text{The remaining sedimentary type, with Sandstone as its example, is Clastic (fragmental)}$
Answer: Clastic (fragmental) sedimentary rock

Since Sandstone is the example under B, and sandstone is made of compacted/cemented rock fragments, B represents the clastic (fragmental) type of sedimentary rock.

Question 64 · 1 pt · constructed response

Compared to the crystal size and cooling rate of the basalt, describe how the crystal size and cooling rate of rock C is different.

earth question 64 figure
Model answer: Rock C (an intrusive igneous rock, e.g., granite) has larger crystals and cooled more slowly than basalt.
Worked solution
$\text{Basalt is extrusive, forming from lava that cools quickly at Earth's surface, producing small/fine crystals}$
$\text{Rock C is intrusive, forming from magma that cools slowly underground}$
$\text{Slower cooling underground allows larger crystals to form in rock C compared to basalt}$
Answer: Rock C (an intrusive igneous rock, e.g., granite) has larger crystals and cooled more slowly than basalt.

Rock C forms intrusively (underground), cooling much more slowly than the extrusive basalt, which results in larger mineral crystals compared to basalt's fine-grained texture.

Question 65 · 1 pt · constructed response

Rock D is composed of coarse-grained mineral crystals that are arranged in light- and dark-colored distorted bands. State the name of rock D.

earth question 65 figure
Model answer: Gneiss
Worked solution
$\text{Rock D is the foliated metamorphic rock example (paired with Marble as the nonfoliated example)}$
$\text{The description of coarse-grained crystals in light and dark distorted/banded layers matches gneiss}$
$\text{Per the ESRT Scheme for Metamorphic Rock Identification, gneiss is described this way}$
Answer: Gneiss

A coarse-grained, banded (light and dark distorted bands) foliated metamorphic rock is identified as gneiss according to the ESRT rock identification chart.

Question 66 · 1 pt · constructed response

Base your answers to questions 66 through 68 on the map and passage below and on your knowledge of Earth science. The map shows the location of Hiawatha crater and a second newly discovered crater in Greenland. These two craters are found under the glacial ice. Second Crater Found in Greenland In 2019, NASA scientists discovered a second crater under Greenland's ice sheet. Using satellite images of the topography beneath the one-mile thick ice sheet, a visible, circular depression was identified. By studying magnetic and gravitational fields, scientists determined a possible cause. If the crater were formed from a volcano, irregular magnetic patterns would be found in the rocks, but none were found. So scientists infer that this crater formed from an impact event. It was determined that the undisturbed ice covering the crater was 79,000 years old, so the impact event must have occurred prior to this time. Explain why this crater was most likely caused by an impact event instead of a past volcanic eruption.

earth question 66 figure
Model answer: No irregular magnetic patterns (which would indicate volcanic rock) were found in the rocks beneath the crater; the absence of this evidence supports an impact origin rather than volcanic activity.
Worked solution
$\text{Volcanic eruptions typically leave irregular magnetic patterns in the rock due to cooling igneous material}$
$\text{Scientists studied the magnetic field of the rocks beneath the crater and found no irregular magnetic patterns}$
$\text{Since volcanic evidence (irregular magnetism) is absent, the crater is inferred to have formed from an impact event instead}$
Answer: No irregular magnetic patterns (which would indicate volcanic rock) were found in the rocks beneath the crater; the absence of this evidence supports an impact origin rather than volcanic activity.

The passage states that no irregular magnetic patterns, which would be expected from volcanic rock, were found, so scientists ruled out a volcanic origin and concluded the crater was formed by an impact event.

Question 67 · 1 pt · constructed response

Base your answers to questions 66 through 68 on the map and passage below and on your knowledge of Earth science. The map shows the location of Hiawatha crater and a second newly discovered crater in Greenland. These two craters are found under the glacial ice. Second Crater Found in Greenland In 2019, NASA scientists discovered a second crater under Greenland's ice sheet. Using satellite images of the topography beneath the one-mile thick ice sheet, a visible, circular depression was identified. By studying magnetic and gravitational fields, scientists determined a possible cause. If the crater were formed from a volcano, irregular magnetic patterns would be found in the rocks, but none were found. So scientists infer that this crater formed from an impact event. It was determined that the undisturbed ice covering the crater was 79,000 years old, so the impact event must have occurred prior to this time. 67 Identify one possible effect on Earth of a major impact event.

earth question 67 figure
Model answer: A major impact event can cause widespread wildfires, tsunamis, earthquakes, or throw large amounts of debris/dust into the atmosphere that blocks sunlight and cools Earth's surface (an impact winter), potentially causing mass extinction of organisms.
Worked solution
$\text{A large impactor striking Earth releases enormous kinetic energy.}$
$\text{This energy can trigger fires, tsunamis, earthquakes, and ejects debris/dust into the atmosphere.}$
$\text{Dust and aerosols blocking sunlight can cool the climate and disrupt ecosystems, potentially causing extinctions.}$
Answer: A major impact event can cause widespread wildfires, tsunamis, earthquakes, or throw large amounts of debris/dust into the atmosphere that blocks sunlight and cools Earth's surface (an impact winter), potentially causing mass extinction of organisms.

Any single well-supported consequence of a large impact event (fires, tsunamis, earthquakes, climate cooling/impact winter, mass extinction) earns credit.

Question 68 · 1 pt · constructed response

(Continuing the passage about the Greenland craters.) 68 Identify one climate factor that most likely contributes to the cold climate of Greenland.

The map shows the location of Hiawatha crater and a second newly discovered crater in Greenland. These two craters are found under the glacial ice. Second Crater Found in Greenland In 2019, NASA scientists discovered a second crater under Greenland's ice sheet. Using satellite images of the topography beneath the one-mile thick ice sheet, a visible, circular depression was identified. By studying magnetic and gravitational fields, scientists determined a possible cause. If the crater were formed from a volcano, irregular magnetic patterns would be found in the rocks, but none were found. So scientists infer that this crater formed from an impact event. It was determined that the undisturbed ice covering the crater was 79,000 years old, so the impact event must have occurred prior to this time.

Model answer: Greenland's high latitude (it lies at roughly 60 to 80 degrees N) causes it to receive sunlight at a low angle of insolation year-round, resulting in a cold climate.
Worked solution
$\text{Greenland is located at a very high latitude, near the Arctic Circle.}$
$\text{High latitudes receive sunlight at a low angle, spreading the energy over a larger area and reducing heating.}$
$\text{This low insolation, along with high elevation and ice/snow albedo, produces a cold climate.}$
Answer: Greenland's high latitude (it lies at roughly 60 to 80 degrees N) causes it to receive sunlight at a low angle of insolation year-round, resulting in a cold climate.

Acceptable climate factors include high latitude, high elevation, or high albedo from snow/ice cover, any one of which contributes to Greenland's cold climate.

Question 69 · 1 pt · constructed response

Base your answers to questions 69 through 72 on the topographic map in your answer booklet, which shows elevations in meters, and on your knowledge of Earth science. The 700-meter and 800-meter contour lines in the western portion of this map are incomplete. Line AB is a reference line on the map. 69 On the map in your answer booklet, complete the 700-meter and 800-meter contour lines in the western portion of this map. Extend the lines to the edge of the map.

earth question 69 figure
Model answer: The 700 m and 800 m contour lines must be drawn continuing smoothly from their existing segments, maintaining the same general shape/spacing as the surrounding contour lines, without crossing any other contour line, and extended so each line reaches the edge of the map.
Worked solution
$\text{Contour lines never cross and must close or run off the map edge.}$
$\text{Extend the existing 700 m segment following the local topographic pattern (spacing similar to neighboring contours) to the map edge.}$
$\text{Repeat for the 800 m contour line, keeping it consistently uphill of the 700 m line.}$
Answer: The 700 m and 800 m contour lines must be drawn continuing smoothly from their existing segments, maintaining the same general shape/spacing as the surrounding contour lines, without crossing any other contour line, and extended so each line reaches the edge of the map.

Full credit requires both contour lines drawn following proper contour rules and reaching the map's western edge; exact path depends on the map provided in the answer booklet.

Question 70 · 1 pt · constructed response

On the grid in your answer booklet, construct a topographic profile along line AB by plotting the elevation of all seven contour lines that cross line AB. Elevations for points A and B have been plotted. Connect all nine plots from A to B.

earth question 70 figure
Model answer: Plot the elevation of each of the seven contour line crossings along AB at the correct horizontal position and elevation, then draw a single smooth line connecting all nine points (A, the seven contour crossings, and B) in order, rounding the profile at hilltops and valley bottoms and not extending it above the highest crossed contour or below the lowest.
Worked solution
$\text{Locate where each of the 7 contour lines crosses line AB on the map.}$
$\text{For each crossing, plot a point on the grid at the corresponding elevation and horizontal distance from A.}$
$\text{Connect all 9 points (A, 7 crossings, B) in order with a single smooth curve following proper profile-construction rules.}$
Answer: Plot the elevation of each of the seven contour line crossings along AB at the correct horizontal position and elevation, then draw a single smooth line connecting all nine points (A, the seven contour crossings, and B) in order, rounding the profile at hilltops and valley bottoms and not extending it above the highest crossed contour or below the lowest.

Full credit requires all nine points plotted at the correct elevations/positions and connected in the correct order forming a smooth profile; the exact values depend on the map in the answer booklet.

Question 71 · 1 pt · constructed response

Identify one possible elevation for the surface of Dunn Pond.

earth question 71 figure
Model answer: Any elevation value that is less than the elevation of the lowest closed contour line surrounding Dunn Pond but greater than or equal to the next contour interval below it (for example, if Dunn Pond is enclosed within the 700-meter contour, an acceptable answer would be any value from 600 m up to, but not including, 700 m, such as 650 m).
Worked solution
$\text{A depression such as a pond is bounded by the lowest closed contour line that surrounds it.}$
$\text{The pond's surface elevation must be less than that lowest contour value and no lower than one contour interval below it.}$
$\text{State any single value within that acceptable range.}$
Answer: Any elevation value that is less than the elevation of the lowest closed contour line surrounding Dunn Pond but greater than or equal to the next contour interval below it (for example, if Dunn Pond is enclosed within the 700-meter contour, an acceptable answer would be any value from 600 m up to, but not including, 700 m, such as 650 m).

Credit is given for any elevation within the correct range implied by the contour lines enclosing Dunn Pond on the map; the exact numeric range depends on the map in the answer booklet.

Question 72 · 1 pt · constructed response

On the table in your answer booklet, place an X in one box in each row to indicate whether each creek is flowing into or out of Dunn Pond.

earth question 72 figure
Model answer: Each creek's flow direction is found by checking whether contour elevations decrease toward the pond (creek flows into the pond) or decrease away from the pond (creek flows out of the pond), since water always flows from higher to lower elevation.
Worked solution
$\text{Water flows from higher elevation to lower elevation.}$
$\text{For each creek, compare the elevations of the contour lines it crosses near Dunn Pond.}$
$\text{If elevation decreases toward the pond, mark 'into'; if elevation decreases away from the pond, mark 'out of.'}$
Answer: Each creek's flow direction is found by checking whether contour elevations decrease toward the pond (creek flows into the pond) or decrease away from the pond (creek flows out of the pond), since water always flows from higher to lower elevation.

Correctly marking each creek's flow direction requires reading the contour elevations that cross each creek on the answer-booklet map.

Question 73 · 1 pt · constructed response

Base your answers to questions 73 through 76 on the passage and diagram below and on your knowledge of Earth science. The diagram represents the formation of a pyrocumulonimbus cloud. Some parts of the diagram are labeled. Pyrocumulonimbus Clouds Normally, cool air keeps smoke from rising high in the atmosphere. However, very intense fires can create giant storm clouds, called pyrocumulonimbus clouds, that can reach heights up to 23 kilometers. Smoke and soot (black carbon particles) can remain at these heights for months and sometimes damage the ozone layer. 73 On the diagram in your answer booklet, place an X on the scale to represent the height in kilometers (km) pyrocumulonimbus clouds can reach. Identify the name of the temperature zone of the atmosphere that corresponds to this height.

The answer booklet diagram includes a vertical height scale in kilometers on which you mark an X at the maximum height stated in the passage (23 km). To name the temperature zone at that height, use the Selected Properties of Earth's Atmosphere chart in the Earth Science Reference Tables: | Temperature Zone | Approximate Altitude Range | |---|---| | Troposphere | 0 to about 12 km | | Stratosphere | about 12 km to 50 km | | Mesosphere | about 50 km to 80 km | | Thermosphere | above about 80 km |

Model answer: The X should be placed at 23 km on the height scale; this height corresponds to the stratosphere (per the Reference Tables for Physical Setting/Earth Science, the stratosphere spans roughly from about 12 km to 50 km and contains the ozone layer).
Worked solution
$\text{The passage states pyrocumulonimbus clouds can reach heights up to 23 km.}$
$\text{Using the Reference Tables atmospheric temperature/height chart, 23 km falls within the stratosphere.}$
$\text{Place the X at 23 km and label the zone 'stratosphere.'}$
Answer: The X should be placed at 23 km on the height scale; this height corresponds to the stratosphere (per the Reference Tables for Physical Setting/Earth Science, the stratosphere spans roughly from about 12 km to 50 km and contains the ozone layer).

The 23 km height given in the passage falls within the stratosphere, the atmospheric layer that contains the ozone layer mentioned in the passage.

Question 74 · 1 pt · constructed response

A damaged ozone layer can have harmful effects on organisms on Earth. Explain how the ozone layer reduces these harmful effects.

Model answer: The ozone layer absorbs most of the Sun's harmful ultraviolet (UV) radiation before it reaches Earth's surface, protecting organisms from UV-related damage such as skin cancer, cataracts, and harm to plant life.
Worked solution
$\text{Ozone molecules in the stratosphere absorb incoming ultraviolet radiation from the Sun.}$
$\text{This absorption prevents most harmful UV radiation from reaching Earth's surface.}$
$\text{Less UV reaching the surface means less damage to living organisms.}$
Answer: The ozone layer absorbs most of the Sun's harmful ultraviolet (UV) radiation before it reaches Earth's surface, protecting organisms from UV-related damage such as skin cancer, cataracts, and harm to plant life.

The ozone layer's key protective function is UV absorption, shielding life on Earth from harmful radiation.

Question 75 · 1 pt · constructed response

Explain how an increase in smoke and soot in the atmosphere normally decreases temperatures on Earth's surface.

Model answer: Smoke and soot particles suspended in the atmosphere reflect and block incoming solar radiation (increasing Earth's albedo), which reduces the amount of insolation that reaches and warms Earth's surface, lowering surface temperatures.
Worked solution
$\text{Smoke and soot particles increase the reflectivity (albedo) of the atmosphere.}$
$\text{More incoming solar radiation is reflected or blocked before reaching Earth's surface.}$
$\text{Less insolation reaching the surface results in lower surface temperatures.}$
Answer: Smoke and soot particles suspended in the atmosphere reflect and block incoming solar radiation (increasing Earth's albedo), which reduces the amount of insolation that reaches and warms Earth's surface, lowering surface temperatures.

Aerosols like smoke and soot typically cool the surface by reflecting/blocking sunlight, reducing the insolation that would otherwise warm the ground.

Question 76 · 1 pt · constructed response

As the wildfires burn, large amounts of carbon dioxide are released into the atmosphere. Explain why scientists are concerned with the release of carbon dioxide into Earth's atmosphere.

Model answer: Carbon dioxide is a greenhouse gas that absorbs outgoing infrared (long-wave) radiation from Earth's surface and re-emits it back toward the surface, trapping heat; increasing CO2 levels enhance this greenhouse effect and contribute to global warming and climate change.
Worked solution
$\text{CO}_2 \text{ is a greenhouse gas that absorbs outgoing long-wave (infrared) radiation.}$
$\text{This trapped energy is re-radiated back toward Earth's surface, warming the atmosphere.}$
$\text{Higher atmospheric CO}_2 \text{ concentrations intensify this greenhouse effect, driving global warming.}$
Answer: Carbon dioxide is a greenhouse gas that absorbs outgoing infrared (long-wave) radiation from Earth's surface and re-emits it back toward the surface, trapping heat; increasing CO2 levels enhance this greenhouse effect and contribute to global warming and climate change.

Scientists are concerned because added atmospheric CO2 strengthens the greenhouse effect, raising global average temperatures and altering climate.

Question 77 · 1 pt · constructed response

Base your answers to questions 77 through 80 on the passage and diagram below and on your knowledge of Earth science. The diagram compares the sizes of seven exoplanets located outside of our solar system in the Trappist-1 system to the sizes of the first four planets in our solar system. Line XY is drawn to indicate the size of the Trappist-1 system if it were located within our own solar system and centered around our Sun. Trappist-1 Exoplanets NASA's Spitzer Space Telescope has revealed seven Earth-sized exoplanets (identified by letters b through h) revolving around a star named Trappist-1. Located about 235 trillion miles from Earth, this system of exoplanets is within our galaxy and can be observed in the constellation Aquarius. Trappist-1 is classified as a dwarf star, with a size that is approximately one-tenth the size of the Sun, and with a surface temperature of approximately 2500 K. All seven of the Trappist-1 planetary orbits are much closer to their host star than Mercury is to our Sun. 77 State the color of the star Trappist-1.

earth question 77 figure
Model answer: Red (a star with a surface temperature of about 2500 K is classified, per the Characteristics of Stars chart in the Reference Tables, as a cool red star/red dwarf).
Worked solution
$\text{Trappist-1 has a surface temperature of approximately 2500 K.}$
$\text{On the Reference Tables' star temperature-color relationship, temperatures around 2500-3500 K correspond to red stars.}$
$\text{Therefore Trappist-1 appears red.}$
Answer: Red (a star with a surface temperature of about 2500 K is classified, per the Characteristics of Stars chart in the Reference Tables, as a cool red star/red dwarf).

Cooler stars (lower surface temperature) appear red, per the standard star color-temperature relationship; Trappist-1's ~2500 K places it in the red range.

Question 78 · 1 pt · constructed response

Identify the planet in our solar system that has a diameter closest to the estimated diameter of the star Trappist-1.

Model answer: Jupiter. Since Trappist-1's diameter is about one-tenth the Sun's diameter (roughly 139,000 km), this is closest to Jupiter's diameter of about 143,000 km, far larger than the diameters of Mercury, Venus, Earth, or Mars.
Worked solution
$\text{Sun's diameter} \approx 1{,}392{,}000\text{ km}$
$\text{Trappist-1 diameter} \approx \tfrac{1}{10}(1{,}392{,}000) \approx 139{,}200\text{ km}$
$\text{Compare to planet diameters; Jupiter} \approx 143{,}000\text{ km is the closest match.}$
Answer: Jupiter. Since Trappist-1's diameter is about one-tenth the Sun's diameter (roughly 139,000 km), this is closest to Jupiter's diameter of about 143,000 km, far larger than the diameters of Mercury, Venus, Earth, or Mars.

Calculating one-tenth of the Sun's diameter gives a value close to Jupiter's actual diameter, making Jupiter the best match among solar system planets.

Question 79 · 1 pt · constructed response

Exoplanet Trappist-1g orbits its star in 12.35 days. Explain why this exoplanet orbits its star in less time than it takes Mercury to orbit our Sun.

The diagram compares the sizes of seven exoplanets located outside of our solar system in the Trappist-1 system to the sizes of the first four planets in our solar system. Line XY is drawn to indicate the size of the Trappist-1 system if it were located within our own solar system and centered around our Sun. Trappist-1 Exoplanets NASA's Spitzer Space Telescope has revealed seven Earth-sized exoplanets (identified by letters b through h) revolving around a star named Trappist-1. Located about 235 trillion miles from Earth, this system of exoplanets is within our galaxy and can be observed in the constellation Aquarius. Trappist-1 is classified as a dwarf star, with a size that is approximately one-tenth the size of the Sun, and with a surface temperature of approximately 2500 K. All seven of the Trappist-1 planetary orbits are much closer to their host star than Mercury is to our Sun.

Model answer: Trappist-1g orbits much closer to its star than Mercury orbits the Sun (as stated in the passage); a planet with a smaller orbital radius has a shorter orbital period, so it completes an orbit in less time than Mercury, which orbits farther from the Sun.
Worked solution
$\text{The passage states all Trappist-1 planetary orbits are much closer to their star than Mercury is to the Sun.}$
$\text{By Kepler's relationship, orbital period increases with orbital distance (radius).}$
$\text{A smaller orbital radius for Trappist-1g means a shorter orbital period than Mercury's ~88-day orbit.}$
Answer: Trappist-1g orbits much closer to its star than Mercury orbits the Sun (as stated in the passage); a planet with a smaller orbital radius has a shorter orbital period, so it completes an orbit in less time than Mercury, which orbits farther from the Sun.

Shorter orbital distance directly produces a shorter orbital period, explaining why Trappist-1g's 12.35-day orbit is faster than Mercury's roughly 88-day orbit.

Question 80 · 1 pt · constructed response

These exoplanets were discovered because the light from Trappist-1 was observed to dim slightly every time an orbiting planet transited (passed in front of) the star. Identify one natural celestial object in our solar system that transits our Sun and temporarily reduces the light that reaches Earth.

Model answer: Venus (or Mercury, or the Moon during a solar eclipse) passes in front of the Sun and temporarily blocks/reduces the amount of sunlight reaching Earth.
Worked solution
$\text{A transit occurs when an object passes directly between an observer and a star.}$
$\text{In our solar system, Venus, Mercury, or the Moon can pass in front of the Sun as seen from Earth.}$
$\text{This passage blocks a small amount of the Sun's light reaching Earth, similar to an exoplanet transit.}$
Answer: Venus (or Mercury, or the Moon during a solar eclipse) passes in front of the Sun and temporarily blocks/reduces the amount of sunlight reaching Earth.

Any celestial body that periodically crosses in front of the Sun as viewed from Earth (Venus, Mercury, or the Moon during an eclipse) is an acceptable answer.

Question 81 · 1 pt · constructed response

Base your answers to questions 81 through 83 on the photographs below and on your knowledge of Earth science. The photographs show samples of sandstone, labeled A through D. (Not drawn to scale) 81 Identify the letter of the sandstone sample that most likely underwent the greatest amount of erosion by a stream and identify evidence shown in the photographs that supports this choice.

earth question 81 figure
Model answer: Sample D; it is the most rounded and smooth (spherical) of the four samples, and rock fragments become more rounded the longer/farther they are eroded and transported by a stream (abrasion wears down sharp edges over time and distance).
Worked solution
$\text{Compare the roundness/shape of samples A, B, C, and D in the photographs.}$
$\text{Sample D is the most rounded and smooth, while A and B appear angular.}$
$\text{Greater rounding indicates greater abrasion and transport distance by a stream.}$
Answer: Sample D; it is the most rounded and smooth (spherical) of the four samples, and rock fragments become more rounded the longer/farther they are eroded and transported by a stream (abrasion wears down sharp edges over time and distance).

Roundness is the key visual evidence of erosion; the most rounded, sphere-like sample (D) shows the greatest amount of stream erosion/abrasion.

Question 82 · 1 pt · constructed response

Sandstone sample C is 2.0 centimeters in diameter. Determine the minimum stream velocity needed to transport this rock sample.

The photographs show samples of sandstone, labeled A through D. (Not drawn to scale)

Model answer: Approximately 100 cm/sec. Using the Reference Tables' 'Relationship Between Particle Size and Water Velocity' graph, a particle with a diameter of 2.0 cm (pebble-sized) requires a stream velocity of about 100 cm/sec to be transported (values from about 90 to 115 cm/sec are typically accepted).
Worked solution
$\text{Particle diameter} = 2.0\text{ cm}$
$\text{Locate 2.0 cm on the horizontal axis of the Reference Tables' particle size vs. velocity graph.}$
$\text{Read the corresponding minimum velocity on the vertical axis} \approx 100\text{ cm/sec.}$
Answer: Approximately 100 cm/sec. Using the Reference Tables' 'Relationship Between Particle Size and Water Velocity' graph, a particle with a diameter of 2.0 cm (pebble-sized) requires a stream velocity of about 100 cm/sec to be transported (values from about 90 to 115 cm/sec are typically accepted).

The Reference Tables graph relating grain diameter to required stream velocity gives roughly 100 cm/sec as the minimum velocity to transport a 2.0 cm particle.

Question 83 · 1 pt · constructed response

Identify the complete range of grain sizes that could be found in each of these rock samples.

The photographs show samples of sandstone, labeled A through D. (Not drawn to scale)

Model answer: 0.006 cm to 0.2 cm. Since all four samples are sandstone, and the Reference Tables define sand-sized particles as ranging from 0.006 cm to 0.2 cm in diameter, this is the complete range of grain sizes possible in each sample.
Worked solution
$\text{All four rock samples are identified as sandstone.}$
$\text{Sandstone is defined as a sedimentary rock composed of sand-sized particles.}$
$\text{Per the Reference Tables, sand-sized particles range from 0.006 cm to 0.2 cm in diameter.}$
Answer: 0.006 cm to 0.2 cm. Since all four samples are sandstone, and the Reference Tables define sand-sized particles as ranging from 0.006 cm to 0.2 cm in diameter, this is the complete range of grain sizes possible in each sample.

By definition, sandstone must be composed only of sand-sized grains, whose diameter range (0.006-0.2 cm) is given in the particle size scale of the Reference Tables.

Question 84 · 1 pt · constructed response

Base your answers to questions 84 and 85 on the data table and Saffir-Simpson Hurricane Scale below, on the map in your answer booklet, and on your knowledge of Earth science. The data table shows latitude and longitude locations of the center of Hurricane Dorian, and the maximum sustained wind speed in miles per hour (mph), each day from August 24 to September 7, 2019. The Saffir-Simpson Hurricane Scale shows the wind speeds associated with each storm category. The map in your answer booklet shows the location of the hurricane from August 24, 2019 through August 31, 2019. Data table (Date: Latitude, Longitude, Maximum sustained wind speed): Aug. 24, 2019: 10.7°N, 49.1°W, 40 mph Aug. 25, 2019: 11.5°N, 54.2°W, 50 mph Aug. 26, 2019: 12.7°N, 58.8°W, 60 mph Aug. 27, 2019: 15.3°N, 62.5°W, 50 mph Aug. 28, 2019: 18.8°N, 65.5°W, 80 mph Aug. 29, 2019: 22.5°N, 67.7°W, 85 mph Aug. 30, 2019: 25.0°N, 70.7°W, 115 mph Aug. 31, 2019: 26.2°N, 74.4°W, 150 mph Sept. 1, 2019: 26.6°N, 77.3°W, 185 mph Sept. 2, 2019: 26.8°N, 78.4°W, 145 mph Sept. 3, 2019: 27.7°N, 78.7°W, 110 mph Sept. 4, 2019: 30.6°N, 79.8°W, 110 mph Sept. 5, 2019: 33.1°N, 78.5°W, 105 mph Sept. 6, 2019: 36.9°N, 72.7°W, 90 mph Sept. 7, 2019: 43.9°N, 63.9°W, 100 mph Saffir-Simpson Hurricane Scale (Classification: Wind Speed mph): Tropical Depression: 0-38 Tropical Storm: 39-73 Category 1 (Hurricane): 74-95 Category 2 (Hurricane): 96-110 Category 3 (Hurricane): 111-130 Category 4 (Hurricane): 131-155 Category 5 (Hurricane): >156 84 On the map in your answer booklet, complete the path of Hurricane Dorian by plotting the location of the storm center for September 1 through September 7. Draw a line to connect all seven of these plots to the August 31 plot to complete the path.

Model answer: Plot each of the seven September locations (Sept. 1: 26.6°N, 77.3°W; Sept. 2: 26.8°N, 78.4°W; Sept. 3: 27.7°N, 78.7°W; Sept. 4: 30.6°N, 79.8°W; Sept. 5: 33.1°N, 78.5°W; Sept. 6: 36.9°N, 72.7°W; Sept. 7: 43.9°N, 63.9°W) on the map using their latitude/longitude coordinates, then draw a single connected line in chronological order starting from the August 31 point through September 7.
Worked solution
$\text{Use each date's latitude and longitude from the table to locate points on the map's coordinate grid.}$
$\text{Plot points for Sept. 1 through Sept. 7 in the same style as the existing Aug. 24-31 plots.}$
$\text{Connect all points in chronological order with a single line beginning at the Aug. 31 plot.}$
Answer: Plot each of the seven September locations (Sept. 1: 26.6°N, 77.3°W; Sept. 2: 26.8°N, 78.4°W; Sept. 3: 27.7°N, 78.7°W; Sept. 4: 30.6°N, 79.8°W; Sept. 5: 33.1°N, 78.5°W; Sept. 6: 36.9°N, 72.7°W; Sept. 7: 43.9°N, 63.9°W) on the map using their latitude/longitude coordinates, then draw a single connected line in chronological order starting from the August 31 point through September 7.

All seven September data points must be plotted at their correct lat/long positions and connected sequentially to the existing path ending on August 31.

Question 85 · 1 pt · constructed response

Use the Saffir-Simpson scale to identify the two dates when Hurricane Dorian changed from a category 4 hurricane to a category 5 hurricane.

Model answer: August 31, 2019 and September 1, 2019. On August 31 the maximum sustained wind speed was 150 mph (Category 4, 131-155 mph range), and on September 1 it rose to 185 mph (Category 5, greater than 156 mph).
Worked solution
$\text{Aug. 31 wind speed} = 150\text{ mph} \Rightarrow \text{Category 4 (131-155 mph)}$
$\text{Sept. 1 wind speed} = 185\text{ mph} \Rightarrow \text{Category 5 (>156 mph)}$
$\text{The transition from Category 4 to Category 5 occurred between these two dates.}$
Answer: August 31, 2019 and September 1, 2019. On August 31 the maximum sustained wind speed was 150 mph (Category 4, 131-155 mph range), and on September 1 it rose to 185 mph (Category 5, greater than 156 mph).

Comparing consecutive daily wind speeds to the Saffir-Simpson scale shows the storm crossed from Category 4 (150 mph) on Aug. 31 to Category 5 (185 mph) on Sept. 1.

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