I85PREP
⌘ K
FTCE Earth/Space Science 008 study materials
FTCE Earth/Space Science 008 study resources

FTCE Earth/Space Science 008 practice questions

One question at a time. Build your FTCE Earth/Space Science 008 understanding.

First 50 of 200 questions. Each one lists the choices, the correct answer, and an explanation. The checker at the top of this page saves progress in this browser when it is available.

Continue in the practice tool above to load more questions, 50 at a time.

Question 1Foundations of Earth and Space Science

Which observation first established that Earth's outer core is liquid?

  1. S-waves cannot pass through it Correct answer.
  2. P-waves cannot pass through it
  3. Body waves refract away from it
  4. Love waves travel faster than Rayleigh waves there

Explanation

S-waves are transverse and cannot propagate through a fluid, so their absence beyond about 103 degrees from an earthquake epicenter reveals a liquid outer core. This seismic shadow zone is the classic evidence for a fluid layer between the mantle and inner core.

Question 2Foundations of Earth and Space Science

The Mohorovicic discontinuity marks the boundary between which two layers?

  1. Lithosphere and asthenosphere
  2. Crust and mantle Correct answer.
  3. Mantle and outer core
  4. Outer core and inner core

Explanation

The Moho is the seismic discontinuity where P-wave velocities jump to about 8 km/s, marking the base of the crust and the top of the mantle. It is defined by a change in composition and seismic velocity rather than by mechanical behavior.

Question 3Foundations of Earth and Space Science

A rock sample contains a mineral that crystallized from magma at high temperature. Which property of that mineral is most useful for identifying it in thin section under a polarizing microscope?

  1. Its density measured in air
  2. Its interference colors between crossed polars Correct answer.
  3. Its electrical conductivity
  4. Its magnetic susceptibility

Explanation

Interference colors arise from the mineral's birefringence and thickness and are diagnostic optical properties observable only with crossed polars. Density, magnetism, and conductivity are bulk properties not observed in thin section.

Question 4Foundations of Earth and Space Science

Which process best explains why the Hawaiian Islands form a linear chain of progressively older volcanoes to the northwest?

  1. A stationary mantle hotspot beneath a moving plate Correct answer.
  2. Seafloor spreading at the East Pacific Rise
  3. Subduction of the Pacific plate along a trench
  4. Continental collision along the Pacific margin

Explanation

A fixed hotspot in the mantle produces volcanism above it while the Pacific plate moves northwest, leaving older, eroded islands behind. The age progression along the chain records plate motion over the hotspot.

Question 5Foundations of Earth and Space Science

Which gas makes up the largest fraction of Earth's current atmosphere by volume?

  1. Carbon dioxide
  2. Argon
  3. Oxygen
  4. Nitrogen Correct answer.

Explanation

Nitrogen constitutes about 78 percent of the dry atmosphere, making it the dominant gas. Oxygen is second at roughly 21 percent, with argon and carbon dioxide present in much smaller amounts.

Question 6Foundations of Earth and Space Science

The Coriolis effect deflects moving air to the right in the Northern Hemisphere because of which cause?

  1. Friction between air and the ground
  2. Earth's rotation Correct answer.
  3. Pressure gradient force
  4. Latent heat release in clouds

Explanation

The Coriolis effect results from Earth's rotation, which causes moving objects to appear deflected relative to the rotating surface. The deflection is to the right in the Northern Hemisphere and to the left in the Southern Hemisphere.

Question 7Foundations of Earth and Space Science

Which of the following best describes the primary cause of ocean tides?

  1. Differential gravitational pull of the Moon and Sun across Earth Correct answer.
  2. Melting of polar ice adding water to the oceans
  3. Convection currents in the mantle
  4. Prevailing winds pushing water against coastlines

Explanation

Tides arise because the Moon and Sun exert slightly different gravitational forces on the near and far sides of Earth, producing two tidal bulges. The Moon dominates because of its proximity.

Question 8Foundations of Earth and Space Science

Which statement correctly describes the relationship between Earth's rotation and revolution?

  1. Both rotation and revolution describe motion about the Sun
  2. Rotation about the Sun produces the year; revolution about its axis produces day and night
  3. Rotation produces seasons; revolution produces day and night
  4. Rotation about its axis produces day and night; revolution about the Sun produces the year Correct answer.

Explanation

Earth rotates on its axis once per day, producing the day-night cycle, and revolves around the Sun once per year. Seasons result from the tilt of the axis combined with revolution, not from rotation alone.

Question 9Foundations of Earth and Space Science

A seismic station records P-wave arrival at 10:00:00 and S-wave arrival at 10:03:20. Using a travel-time curve where each 40-second S-minus-P interval corresponds to about 350 km of distance, approximately how far is the epicenter?

  1. 2,100 km
  2. 350 km
  3. 700 km
  4. 1,750 km Correct answer.

Explanation

The S-minus-P interval is 200 seconds, which is five 40-second units. Multiplying five by 350 km gives about 1,750 km, the standard method for locating an epicenter from a single station's lag time.

Question 10Foundations of Earth and Space Science

A mineral specimen has a hardness of 6.5, no cleavage, and a vitreous luster. Which identification is most consistent with these properties?

  1. Gypsum
  2. Calcite
  3. Quartz Correct answer.
  4. Talc

Explanation

Quartz has a Mohs hardness of 7, lacks cleavage, and shows a vitreous luster, matching the description closely. Calcite, gypsum, and talc are all softer and have distinct cleavage.

Question 11Foundations of Earth and Space Science

In a sequence of undeformed sedimentary rock layers, a dike cuts across all layers. Which principle establishes that the dike is younger than the layers?

  1. Principle of faunal succession
  2. Principle of cross-cutting relationships Correct answer.
  3. Principle of original horizontality
  4. Principle of superposition

Explanation

The principle of cross-cutting relationships states that a feature cutting across another must be younger than the material it cuts. A dike that penetrates all layers therefore postdates them.

Question 12Foundations of Earth and Space Science

A radioactive isotope has a half-life of 50 million years. If a mineral contains 25 percent of the parent isotope and 75 percent of the daughter, how old is the mineral?

  1. 100 million years Correct answer.
  2. 150 million years
  3. 200 million years
  4. 50 million years

Explanation

With 25 percent parent remaining, two half-lives have elapsed (50 percent, then 25 percent). Two half-lives at 50 million years each give an age of 100 million years.

Question 13Foundations of Earth and Space Science

An air mass forms over a warm, dry desert and moves over a moist region. What change in its properties is most likely as it moves?

  1. It becomes cooler and more humid Correct answer.
  2. It becomes warmer and drier
  3. It remains unchanged in temperature and humidity
  4. It becomes colder and drier

Explanation

A continental tropical air mass moving over a moist region gains moisture and loses heat through evaporation and mixing. Its temperature decreases and its humidity increases as it modifies.

Question 14Foundations of Earth and Space Science

A parcel of unsaturated air at 20 degrees Celsius with a dew point of 10 degrees Celsius is lifted. At approximately what altitude does cloud formation begin, assuming the dry adiabatic lapse rate and a typical dew point lapse rate?

  1. About 1 km Correct answer.
  2. About 5 km
  3. About 3 km
  4. About 0.5 km

Explanation

The lifting condensation level is roughly 125 meters per degree of dew point depression. A 10-degree depression gives about 1.25 km, closest to 1 km among the choices.

Question 15Foundations of Earth and Space Science

A star's spectrum shows its peak emission at a wavelength of 500 nanometers. Using Wien's law, what is the approximate surface temperature of the star?

  1. 20,000 K
  2. 3,000 K
  3. 5,800 K Correct answer.
  4. 10,000 K

Explanation

Wien's law gives T equals 2.9 times 10 to the minus 3 meter-kelvin divided by the peak wavelength in meters. Substituting 500 nanometers yields about 5,800 K, close to the Sun's temperature.

Question 16Foundations of Earth and Space Science

During a solar eclipse, the Moon passes directly between Earth and the Sun. Which condition must also be satisfied for a total eclipse to occur?

  1. Earth must be at perihelion
  2. The Sun must be near solar maximum
  3. The Moon must be at apogee
  4. The Moon must be near a node of its orbit Correct answer.

Explanation

A solar eclipse occurs only when the new Moon aligns with the Sun near a node of the Moon's tilted orbit. Otherwise the shadow misses Earth because of the five-degree orbital inclination.

Question 17Foundations of Earth and Space Science

The apparent daily motion of stars around the celestial pole is caused primarily by which phenomenon?

  1. Earth's rotation on its axis Correct answer.
  2. Precession of Earth's axis
  3. Proper motion of the stars
  4. Earth's revolution around the Sun

Explanation

Earth's rotation once per day makes the entire celestial sphere appear to turn around the celestial poles. Revolution produces annual changes such as different constellations visible by season.

Question 18Foundations of Earth and Space Science

A rock formed from a magma that cooled slowly at depth would most likely have which texture?

  1. Glassy
  2. Vesicular
  3. Fine-grained aphanitic
  4. Coarse-grained phaneritic Correct answer.

Explanation

Slow cooling at depth allows crystals to grow large, producing a coarse-grained phaneritic texture. Rapid cooling at the surface produces fine-grained or glassy rocks.

Question 19Foundations of Earth and Space Science

Which of the following best explains why the sky appears blue?

  1. Air molecules scatter short wavelengths more strongly than long wavelengths Correct answer.
  2. The ozone layer reflects blue light toward the surface
  3. Sunlight is intrinsically more intense at blue wavelengths
  4. Water vapor absorbs red light in the atmosphere

Explanation

Rayleigh scattering by atmospheric molecules varies inversely with the fourth power of wavelength, so blue light is scattered far more than red. That scattered blue light reaches the observer from all directions.

Question 20Foundations of Earth and Space Science

A metamorphic rock shows alternating light and dark bands. Which metamorphic grade and rock type does this texture indicate?

  1. Contact-metamorphosed hornfels
  2. Low-grade slate
  3. Unmetamorphosed sandstone
  4. High-grade gneiss Correct answer.

Explanation

Banding of light and dark minerals is gneissic texture, typical of high-grade regional metamorphism. Slate and hornfels lack such banding.

Question 21Foundations of Earth and Space Science

A stream's discharge increases sharply after a storm, but its velocity stays nearly constant. Which change best explains the increase in discharge?

  1. The channel cross-sectional area increased Correct answer.
  2. The stream's gradient decreased
  3. The sediment load decreased
  4. The water temperature rose

Explanation

Discharge equals cross-sectional area times velocity. If velocity is constant while discharge rises, the channel cross-sectional area must have increased, as when stage rises.

Question 22Foundations of Earth and Space Science

Two stars have the same luminosity, but star A is twice as far away as star B. How does the apparent brightness of A compare with that of B?

  1. A is one-half as bright
  2. A is one-fourth as bright Correct answer.
  3. A is four times brighter
  4. A is twice as bright

Explanation

Apparent brightness follows an inverse-square law, so doubling the distance reduces brightness by a factor of four. With equal luminosities, star A appears one-fourth as bright as star B.

Question 23Foundations of Earth and Space Science

Magnetic striping on the seafloor is symmetric about mid-ocean ridges. Which conclusion follows most directly from this pattern?

  1. Continents drift without changing ocean width
  2. Ocean basins never change in size
  3. The mantle is completely molten beneath ridges
  4. The seafloor spreads outward from ridges as the field reverses Correct answer.

Explanation

Symmetrical magnetic stripes record reversals of Earth's field frozen into new crust as it forms at the ridge and moves away on both sides. This pattern is a key confirmation of seafloor spreading.

Question 24Foundations of Earth and Space Science

Isotopic analysis of a meteorite shows an excess of a daughter isotope relative to the parent. If the system remained closed, which interpretation is most defensible?

  1. The parent isotope decayed faster in space
  2. The meteorite is older than a sample with less daughter enrichment Correct answer.
  3. The meteorite formed recently
  4. The meteorite experienced melting that reset the clock

Explanation

In a closed system, more daughter enrichment means more half-lives have elapsed, so the sample is older. Melting or other disturbance would reset the isotopic clock and violate the closed-system assumption.

Question 25Foundations of Earth and Space Science

A coastal region experiences a strong upwelling along its western shore. Which consequence is most likely?

  1. Sea level rises sharply along the coast
  2. Surface water becomes cooler and nutrient-rich Correct answer.
  3. Surface water becomes warmer and nutrient-poor
  4. Salinity drops to near zero

Explanation

Upwelling brings cold, nutrient-rich water from depth to the surface, supporting high productivity. It does not warm the surface or freshen it dramatically.

Question 26Foundations of Earth and Space Science

A geologist classifies a specimen as a mineral rather than a rock primarily because a mineral must satisfy which set of criteria?

  1. Produced in a laboratory, synthetic in origin, and amorphous in structure
  2. Composed of two or more minerals and lacking a crystalline structure
  3. Formed by organisms, containing carbon, and having a variable composition
  4. Naturally occurring, inorganic, definite chemical composition, and ordered internal structure Correct answer.

Explanation

A mineral is defined as a naturally occurring, inorganic solid with a definite chemical composition and an ordered internal arrangement of atoms. A rock, by contrast, is an aggregate of one or more minerals and need not have a single composition. The definition excludes synthetic substances and organic materials such as shell or wood.

Question 27Foundations of Earth and Space Science

A student compares two igneous rocks: one cooled from lava at Earth's surface, the other from magma at depth. Which pair of textures is expected?

  1. Fine-grained for the surface rock and coarse-grained for the deep rock Correct answer.
  2. Coarse-grained for the surface rock and fine-grained for the deep rock
  3. Glass for the deep rock and coarse-grained for the surface rock
  4. Vesicular for the deep rock and fine-grained for the surface rock

Explanation

Cooling rate controls crystal size: rapid cooling at the surface produces many small crystals (fine-grained), while slow cooling at depth allows crystals to grow large (coarse-grained). This is why extrusive rocks such as basalt are fine-grained and intrusive rocks such as granite are coarse-grained.

Question 28Foundations of Earth and Space Science

Which layer of Earth's interior is best described as behaving plastically and flowing slowly, allowing tectonic plates to move over it?

  1. The asthenosphere Correct answer.
  2. The outer core
  3. The inner core
  4. The lithosphere

Explanation

The asthenosphere lies beneath the rigid lithosphere and is partially molten, so it deforms plastically over geologic time. Plate motion is accommodated by flow within this weak layer. The lithosphere is rigid, and the cores are metallic and far below the plates.

Question 29Foundations of Earth and Space Science

A rock sample contains abundant fossils of marine shells and is composed of cemented shell fragments. Which rock type and origin does this best indicate?

  1. Igneous, formed by crystallization of a melt
  2. Sedimentary, formed by precipitation from a cooling hydrothermal fluid
  3. Metamorphic, formed by recrystallization under heat and pressure
  4. Sedimentary, formed by accumulation and lithification of biological debris Correct answer.

Explanation

Fossil-rich rocks made of shell material are sedimentary rocks produced when biological debris accumulates, is buried, and is lithified. Fossils are preserved mainly in sedimentary rocks because melting or intense recrystallization destroys them.

Question 30Foundations of Earth and Space Science

Which process is the principal driver of plate tectonics, moving lithospheric plates across Earth's surface?

  1. Convection in the mantle driven by heat from Earth's interior Correct answer.
  2. Rotation of Earth generating centrifugal force on the crust
  3. Meteorite impacts pushing plates outward from impact sites
  4. Tidal forces exerted by the Moon on the crust

Explanation

Mantle convection, together with slab pull and ridge push, transfers heat from Earth's interior and provides the forces that move plates. Tidal and rotational forces are far too weak to displace lithospheric plates.

Question 31Foundations of Earth and Space Science

Which characteristic distinguishes a transform plate boundary from a divergent boundary?

  1. Plates converge and compressional mountains form
  2. Plates move apart and new oceanic lithosphere is created
  3. Plates collide and one is subducted beneath the other
  4. Plates slide horizontally past one another with no lithosphere created or destroyed Correct answer.

Explanation

At a transform boundary, lithospheric plates move horizontally past each other, producing strike-slip faults and shallow earthquakes without creating or consuming crust. Divergent boundaries create new lithosphere, and convergent boundaries destroy or thicken it.

Question 32Foundations of Earth and Space Science

The greenhouse effect warms Earth's surface primarily because certain atmospheric gases do which of the following?

  1. Prevent convection from carrying heat upward in the troposphere
  2. Reflect incoming visible sunlight back into space before it reaches the ground
  3. Generate heat directly through chemical reactions with oxygen
  4. Absorb outgoing infrared radiation and re-emit energy toward the surface Correct answer.

Explanation

Greenhouse gases such as water vapor and carbon dioxide are transparent to incoming visible light but absorb outgoing infrared radiation, re-emitting part of it back toward the surface. This reduces the net loss of energy to space and raises surface temperature.

Question 33Foundations of Earth and Space Science

Which statement correctly describes Earth's magnetic field as recorded in rocks?

  1. Its polarity has reversed many times, and the record is preserved in magnetized minerals of cooling lava Correct answer.
  2. It has always pointed in the same direction since Earth formed
  3. It is produced by permanent magnetism of the entire mantle
  4. It is strongest at the equator and weakest at the poles

Explanation

When lava cools below the Curie temperature, magnetic minerals lock in the direction of the ambient field, recording polarity. Studies of this record show numerous reversals over geologic time, which is the basis of magnetostratigraphy.

Question 34Foundations of Earth and Space Science

A sample of granite contains 12.5 percent of its original radioactive parent isotope. If the half-life is 200 million years, what is the age of the sample?

  1. 200 million years
  2. 400 million years
  3. 600 million years Correct answer.
  4. 800 million years

Explanation

Each half-life reduces the parent fraction by half: 100 percent, 50 percent, 25 percent, then 12.5 percent after three half-lives. Three half-lives of 200 million years each give 600 million years.

Question 35Foundations of Earth and Space Science

A geologist observes that a fault cuts through a sedimentary layer but does not extend into the layer above it. Which conclusion follows?

  1. The fault formed before the lower layer was deposited
  2. The fault and the upper layer formed at exactly the same time
  3. The upper layer is older than the fault
  4. The fault formed after the lower layer was deposited but before the upper layer was deposited Correct answer.

Explanation

Cross-cutting relationships state that a feature which cuts another is younger than the material it cuts. Because the fault cuts the lower bed but is truncated by the upper bed, the fault postdates the lower layer and predates the upper one.

Question 36Foundations of Earth and Space Science

A region experiences seasonal monsoons in which summer winds blow from ocean to land. Which mechanism best explains the seasonal reversal of wind direction?

  1. The Coriolis effect reverses direction between summer and winter
  2. Earth's magnetic field shifts seasonally and steers the winds
  3. Ocean salinity changes reverse the prevailing wind belts
  4. Differential heating of land and sea creates a seasonal pressure gradient that reverses Correct answer.

Explanation

Land heats and cools faster than water, so in summer the land is warmer and lower in pressure, drawing moist air from the cooler ocean. In winter the pattern reverses, producing the seasonal wind reversal characteristic of monsoons.

Question 37Foundations of Earth and Space Science

A cold front overtakes a warm front, lifting the warm air mass entirely off the ground. Which weather sequence is most likely at the surface?

  1. Clear skies with rising temperatures and decreasing pressure
  2. A gradual temperature rise with light, prolonged drizzle
  3. A period of steady precipitation followed by clearing and cooler, drier air Correct answer.
  4. Warm, humid conditions persisting for many days with no precipitation

Explanation

In an occluded front the cold front lifts the warm air aloft, producing precipitation that ends as the system passes. Behind the occlusion, cooler and drier air typically arrives, bringing clearing conditions.

Question 38Foundations of Earth and Space Science

A parcel of air at 25 degrees Celsius holds 10 grams of water vapor per kilogram of air. Its saturation mixing ratio at that temperature is 20 grams per kilogram. What is the relative humidity?

  1. 20 percent
  2. 50 percent Correct answer.
  3. 10 percent
  4. 200 percent

Explanation

Relative humidity is the actual mixing ratio divided by the saturation mixing ratio, multiplied by 100. Here 10 divided by 20 equals 0.5, or 50 percent.

Question 39Foundations of Earth and Space Science

A stream flows from a mountainous source to a broad, flat plain. How do channel gradient, velocity, and sediment size typically change downstream?

  1. Gradient decreases, velocity generally decreases, and sediment becomes finer Correct answer.
  2. Gradient increases, velocity increases, and sediment becomes coarser
  3. Gradient decreases, velocity increases, and sediment becomes coarser
  4. Gradient remains constant and sediment size is unchanged

Explanation

Downstream the channel gradient flattens and discharge is spread over a wider, shallower channel, so velocity generally decreases. The reduced competence of the stream allows only finer sediment to be transported, so deposits become finer downstream.

Question 40Foundations of Earth and Space Science

Which feature forms where a stream enters a standing body of water and its velocity drops abruptly?

  1. A meander
  2. A point bar
  3. A delta Correct answer.
  4. An oxbow lake

Explanation

When a stream enters a lake or sea, its velocity falls sharply and the sediment load is deposited, building a delta. Meanders, point bars, and oxbow lakes form along the stream channel rather than at its mouth.

Question 41Foundations of Earth and Space Science

A glacier's terminus retreats while the ice continues to flow forward. Which condition explains this observation?

  1. The glacier is advancing because the terminus moves downslope
  2. Ice flow has stopped completely at the terminus
  3. Accumulation exceeds ablation, causing the glacier to advance
  4. Ablation at the terminus exceeds accumulation in the zone of accumulation Correct answer.

Explanation

A glacier retreats when the rate of ice loss by melting and calving exceeds the rate of ice supply from accumulation. The ice still flows forward, but the terminus position moves upvalley because loss outpaces supply.

Question 42Foundations of Earth and Space Science

Which evidence most directly supports the conclusion that Earth's outer core is liquid?

  1. Earthquake foci occur only in the upper mantle
  2. The Moho marks a change in seismic velocity at the crust-mantle boundary
  3. S-waves do not propagate through the outer core, creating a seismic shadow zone Correct answer.
  4. P-waves travel faster through the mantle than through the crust

Explanation

S-waves cannot pass through liquids, and their absence beyond about 103 degrees from an earthquake confirms a liquid outer core. The P-wave shadow zone, caused by refraction at the core boundary, provides additional evidence.

Question 43Foundations of Earth and Space Science

A star is observed to have a parallax angle of 0.1 arcsecond. What is its approximate distance in parsecs?

  1. 10 parsecs Correct answer.
  2. 1 parsec
  3. 0.1 parsec
  4. 100 parsecs

Explanation

Distance in parsecs is the reciprocal of the parallax angle in arcseconds. For 0.1 arcsecond, the distance is 1 divided by 0.1, or 10 parsecs.

Question 44Foundations of Earth and Space Science

A main-sequence star has a surface temperature of about 6,000 kelvin. Which spectral class and color are most consistent with this value?

  1. O class, blue
  2. G class, yellow Correct answer.
  3. A class, white
  4. M class, red

Explanation

The spectral sequence runs O, B, A, F, G, K, M from hottest to coolest. A temperature near 6,000 kelvin falls in the G class, whose stars such as the Sun appear yellow.

Question 45Foundations of Earth and Space Science

A lunar eclipse occurs only at full moon, yet not every full moon produces an eclipse. Which condition explains this?

  1. The Moon's orbital plane is inclined about 5 degrees to the ecliptic, so it usually passes above or below Earth's shadow Correct answer.
  2. The Moon is too small to enter Earth's shadow at most full moons
  3. Earth's atmosphere bends all light around the Moon at full moon
  4. The Moon's rotation slows during full moon so it stops moving

Explanation

The Moon's orbit is tilted about 5 degrees relative to Earth's orbital plane, so at most full moons the Moon misses Earth's shadow. Eclipses occur only near the nodes, where the orbital planes intersect.

Question 46Foundations of Earth and Space Science

A sedimentary sequence shows a gradual change from coarse sandstone at the bottom to shale at the top. Which interpretation is most consistent with this pattern?

  1. Depositional energy decreased over time as the environment changed Correct answer.
  2. Sea level fell steadily during deposition
  3. The sequence was overturned by tectonic folding
  4. Depositional energy increased over time as the environment changed

Explanation

Coarse grains settle in higher-energy environments, whereas fine mud requires quiet water. An upward transition from sandstone to shale therefore records decreasing energy, such as a deepening or transgressive setting.

Question 47Foundations of Earth and Space Science

A metamorphic rock contains index minerals that indicate formation at about 500 degrees Celsius and moderate pressure. Which grade and rock type are most consistent with this condition?

  1. No metamorphism, indicated by preserved sedimentary fossils
  2. Low grade, indicated by chlorite and slate texture
  3. Medium grade, indicated by minerals such as garnet or staurolite Correct answer.
  4. Very high grade, indicated by partial melting and migmatite

Explanation

Index minerals record progressive metamorphism: chlorite indicates low grade, and garnet and staurolite appear at medium grades. Temperatures near 500 degrees Celsius with moderate pressure fall in the medium-grade field.

Question 48Foundations of Earth and Space Science

Two coastal cities at the same latitude experience different seasonal temperature ranges: one has a small range, the other a large range. Which factor best explains the difference?

  1. The inland city receives more direct sunlight because of its elevation
  2. The coastal city experiences stronger Coriolis deflection
  3. The coastal city is closer to the equator than the inland city
  4. The city near the ocean is moderated by water's high specific heat, while the inland city is not Correct answer.

Explanation

Water has a high specific heat and mixes, so maritime climates warm and cool slowly, giving small seasonal ranges. Continental interiors heat and cool rapidly, producing larger ranges, a contrast known as continentality.

Question 49Foundations of Earth and Space Science

A supernova remnant expands into the interstellar medium. Which observation would best indicate that the expansion is interacting strongly with surrounding gas?

  1. A constant radio luminosity with no structural change
  2. A redshifted spectrum indicating motion away from Earth
  3. A steady decrease in the remnant's angular size over decades
  4. Enhanced X-ray emission from shock-heated gas at the remnant's edge Correct answer.

Explanation

When ejecta sweep into dense interstellar gas, shocks heat the material to millions of kelvin, producing strong X-ray emission at the interface. This is a direct signature of interaction with the surrounding medium.

Question 50Foundations of Earth and Space Science

A region of seafloor shows magnetic stripes of alternating polarity that are symmetric about a ridge axis. Which conclusion follows most directly?

  1. The ridge has been consuming crust symmetrically on both sides
  2. The seafloor has remained stationary while Earth's magnetic poles drifted
  3. Sediment deposition created the stripes after the crust formed
  4. New oceanic crust formed at the ridge and spread outward while the field reversed periodically Correct answer.

Explanation

Symmetric magnetic stripes record crust that formed at the ridge during alternating polarity intervals and then moved away on both sides. This pattern was a key line of evidence for seafloor spreading.