Study Guide

Earth Science
Sample Questions

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Competency 0001
Demonstrate knowledge of the origin, evolution, and structure of the universe.

1. Use the information below to answer the question that follows.

Two methods for detecting exoplanets are the transit method (dimming of a star) and the radial velocity method (wobble of a star).

In contrast to the radial velocity method for detecting an exoplanet, astronomers can only use the transit method when the:

  1. planet moves very slowly in its orbit around the star.
  2. star does not produce flares or other ejections of radiation.
  3. star around which the planet orbits is very large and bright.
  4. planet's orbit is on the same plane as the line of sight from Earth.
Enter to expand or collapse answer.Answer expanded
Correct Response: D. The transit method for detecting an exoplanet involves measuring the dimming of the star's brightness as a planet moves between the star and Earth. This movement by the planet blocks some of the star's light from reaching Earth and occurs when the plane of the planet's orbit directly crosses the line-of-sight between Earth and the star.

Competency 0002
Apply knowledge of stars and their life cycles.

2. The sun maintains a fixed size and shape regardless of the immense inwardly directed gravitational forces that it exerts upon itself. Which of the following statements best explains why the sun does not collapse under this force?

  1. Explosive forces created by the process of fusion in the sun's core propel particles outward and create an explosive pressure.
  2. A strong centripetal force produced by the sun's rapid rotation exerts an outward physical pressure.
  3. Heat produced in the sun's core causes gases to expand and creates a thermal pressure.
  4. The gravity of the other objects that orbit the sun exert an attractive force.
Enter to expand or collapse answer.Answer expanded
Correct Response: C. Fusion reactions in the core of the sun produce immense quantities of energy. The heat produced by these reactions creates outward pressure that counterbalances the tendency for the star to collapse due to the inward force of gravity. Since the rate of fusion depends on the magnitude of the gravitational force compressing the core, the outward thermal pressure and the inward gravitational pressure tend to remain in equilibrium.

Competency 0003
Analyze the solar system and the interactions of the Earth-sun-moon system.

3. Use the table below to answer the question that follows.

Line Solar Eclipse Lunar Eclipse
1 new full
2 new new
3 full new
4 full full

Which line in the table best represents the correct association of the phases of the moon and the chance of an eclipse occurring?

  1. line 1
  2. line 2
  3. line 3
  4. line 4
Enter to expand or collapse answer.Answer expanded
Correct Response: A. A solar eclipse occurs when the moon is in a position between Earth and the sun. A lunar eclipse occurs when Earth is in a position between the sun and the moon. The moon is in a position between Earth and the sun during a new moon, and Earth is in a position between the sun and the moon during a full moon. Eclipses do not occur during every new and full moon because the plane of the moon's orbit is tilted relative to the plane of Earth's orbit around the sun.

Competency 0004
Apply knowledge of Earth's internal structure and the history of Earth.

4. It is commonly accepted that much of the oxygen ( O 2 ) in Earth's early atmosphere was produced by the action of photosynthetic prokaryotes, such as blue-green algae. However, there may have been as many as a billion years between the time that these prokaryotes first appeared and the rapid rise in  O 2  in the oceans and atmosphere known as the Great Oxygenation Event. Which of the following statements best explains this interval?

  1. Due to their small nature, photosynthetic prokaryotes only produce a minimal amount of oxygen, so the rise in  O 2  in the oceans and atmosphere occurred after plants evolved.
  2. Atmospheric  O 2  was quickly broken down into ozone, and it was not until the ozone layer was fully developed that levels of molecular oxygen in the atmosphere were able to rise.
  3. Early Earth was extremely hot, which led to photosynthetic bacteria being confined to small oceans, keeping their population numbers and overall  O 2  production low.
  4. Most of the  O 2  produced was quickly bound into iron compounds in seawater, which meant that it could not exist as free oxygen until these oxygen sinks were filled.
Enter to expand or collapse answer.Answer expanded
Correct Response: D. Iron is highly reactive with free oxygen. Large deposits of banded iron oxides date from the time just before the Great Oxygenation Event. Formation of these deposits must have removed and bound large amounts of oxygen produced by photosynthetic prokaryotes in seawater. It was only when these natural oxygen sinks had been filled that oxygen could accumulate, first in seawater and then in the atmosphere.

Competency 0005
Analyze plate tectonics and the impact of plate movement.

5. The fact that mountain ranges along the west coast of South America and along the North Pacific basin are primarily composed of andesite indicates that these mountains were formed from magma that was:

  1. produced by the melting of crustal rocks deep within a subduction zone.
  2. brought to the surface by a hot spot after originating deep within the mantle.
  3. produced by friction melting as plates rubbed together along a transform fault.
  4. brought to the surface by upwelling from within the asthenosphere at a divergent plate boundary.
Enter to expand or collapse answer.Answer expanded
Correct Response: A. Andesite is an extrusive igneous rock that is intermediate in composition between basalt and granitic rocks, such as rhyolite. In general, oceanic crust is composed primarily of lower-silica basaltic rocks, while continental crust is composed primarily of higher-silica granitic rocks. Andesitic mountains, therefore, have been formed from the intermixing of magmas derived from melting of both oceanic and continental crust, which occurs deep in subduction zones.

Competency 0006
Apply knowledge of Earth materials, the rock cycle, and the processes of weathering, erosion, and deposition.

6. Use the table below to answer the question that follows.

Streak Color Hardness Specific Gravity
none multiple 7 2.6

Which of the following minerals best fits the characteristics shown on the chart?

  1. graphite
  2. quartz
  3. gypsum
  4. calcite
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Correct Response: B. Of the four minerals given, quartz is the only one with a hardness above 3 on the Mohs Hardness Scale. Besides being much harder than the other minerals given, quartz lacks a streak, comes in multiple colors (e.g., rose, amethyst) due to its ability to grow in many environments and therefore garner different impurities, and is relatively dense.

Competency 0007
Demonstrate knowledge of the processes of the hydrosphere and characteristics of oceanic and freshwater systems.

7. Which of the following processes releases energy into the environment?

  1. the evaporation of water from pavement after a summer rainfall
  2. the condensation of water vapor into fog on a cool fall morning
  3. the sublimation of water molecules from the surface of a glacier
  4. the transformation of frost into water droplets as the sun rises
Enter to expand or collapse answer.Answer expanded
Correct Response: B. The latent heat of water is energy that is supplied or removed from water to change its phase without changing its temperature. Thus, as water changes state from a liquid to a gas during evaporation, energy is stored within the bonds between water vapor molecules. When the water vapor cools, liquid water is formed by condensation and the stored energy is released. The formation of fog, which is composed of tiny droplets of liquid water, is one example of condensation and the accompanying release of energy.

Competency 0008
Demonstrate knowledge of the composition, structure, and processes of the atmosphere.

8. The energy transfer that occurs between latitudes as a result of major hurricanes is primarily due to which of the following mechanisms?

  1. The evaporation and condensation of water vapor during the life of a hurricane transfer heat from the surface of tropical oceans to the atmosphere, where it is carried north.
  2. Deep low pressure generated by hurricanes allows the expansion and cooling of warm tropical air masses as they move north.
  3. The downdrafts and updrafts associated with hurricanes mix cold air in the lower atmosphere with hot tropical air masses that are near the surface.
  4. Strong winds produced by hurricanes pull cold northern air masses southward toward the midlatitudes.
Enter to expand or collapse answer.Answer expanded
Correct Response: A. During evaporation, energy is stored within bonds between water molecules as latent heat. As water vapor cools and condenses, the latent heat is released as energy into the environment. Water evaporates from the surface of the ocean, with the rate of evaporation increasing as sea-surface temperature increases. High rates of evaporation from tropical oceans place large amounts of water vapor into the atmosphere, which carry with them energy as latent heat. This energy is released when water vapor cools as it rises and moves into cooler latitudes, forming powerful storms, including hurricanes.

Competency 0009
Demonstrate knowledge of Earth's weather and climate.

9. In early fall in northern Missouri, a fast-moving continental polar air mass collides with a stationary maritime tropical air mass. Which of the following statements describes the most likely weather changes that will occur as a result of this event?

  1. Skies will be partly overcast with cirrus clouds, followed by a brief period of rain and a rise in temperature for a few days.
  2. Clear skies will gradually become overcast with stratus clouds, followed by several days of steady drizzle and periodic fog.
  3. Skies will remain clear with a few cumulus clouds moving into the area, followed by dry weather and a drop in temperature.
  4. Clear skies will be replaced by rapidly forming cumulonimbus clouds, followed by thunderstorms and then gradual clearing.
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Correct Response: D. Cold air is more dense than warm air and contains less water vapor. Thus, when a cold air mass collides with a warm air mass, the lighter warm air is forced upwards. As the warmer air rises, water vapor condenses, releasing energy and forming clouds. Eventually, if enough water vapor is present, precipitation will occur. If a rapidly moving cold air mass collides with a stationary warm mass, the sequence of uplift, condensation, cloud formation, and release of energy will be rapid and thunderstorms are likely to occur.

Competency 0010
Analyze geochemical cycles, natural resources, and energy.

10. Use the information below to answer the question that follows.

For centuries, spring flooding of the Nile River would deposit a layer of fresh, fertile silt upon the fields of resident farmers. The Nile floodplain was one of the most fertile areas in the world, and Egypt was the breadbasket of the Mediterranean basin in ancient times. Currently, the deposition of silt has almost stopped and farmers along the Nile must rely on animal manures and expensive fertilizers to replenish the soil.

The decline in silt deposition on the Nile floodplain has been largely due to which of the following factors?

  1. the deepening of the river to facilitate shipping
  2. the overexploitation of aquifers for irrigation agriculture
  3. the construction of a large dam near the river's headwaters
  4. the release of large quantities of greenhouse gases into the atmosphere
Enter to expand or collapse answer.Answer expanded
Correct Response: C. The Nile River originates in the highlands of East Africa. In the spring, snowmelt and rainfall swell the river, increasing erosion and the sediment load. In the past, when the river entered the lowlands and the reduced gradient caused the river's velocity to slow and flood its banks, silt would settle out and become fertile soil. With the construction of the Aswan High Dam on the Upper Nile, the velocity of the river slows as it enters the vast Lake Nassar behind the dam. Sediment settles out behind the dam onto the bottom of Lake Nassar. It is therefore no longer carried downstream to be deposited along the lower stretches of the river.

Competency 0011
Demonstrate knowledge of natural hazards and their effects on human societies.

11. Which of the following strategies would be most practical and effective at reducing deaths and property damage from large earthquakes?

  1. deploying early warning systems that allow evacuation of populated areas well before an earthquake occurs
  2. passing and enforcing building codes that require all construction to incorporate earthquake-resistant features into their design
  3. using local zoning laws to prevent construction in areas that are prone to earthquakes or that have experienced earthquakes in the past
  4. using controlled drilling and small underground explosions to relieve strain along faults that are likely to produce an earthquake in the near future
Enter to expand or collapse answer.Answer expanded
Correct Response: B. In real time, earthquakes are the least predictable natural hazard. Although large-scale areas that are generally susceptible to earthquakes can be identified (e.g., Southern California), specific locations of earthquake epicenters cannot be predicted accurately in space or time. Earthquakes also cannot be prevented from occurring using any known technology. Given this lack of both predictability and preventability, the most useful strategy for reducing death and destruction due to an earthquake is to incorporate earthquake-resistant designs into building constructions.

Competency 0012
Demonstrate knowledge of the effects and mitigation of human activities on Earth systems.

12. For a class project, several students are working as a team to design a sanitary landfill. Which of the following features of the landfill would be most important for the students to include to reduce the landfill's environmental impact?

  1. removing all vegetation around the landfill
  2. locating the landfill in a hollow between hillsides
  3. placing an impermeable layer at the bottom of the landfill
  4. designating separate dumping areas for different types of trash in the landfill
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Correct Response: C. By far the most important environmental effect of a poorly constructed landfill is the leaching of heavy metals, toxic chemicals, and other pollutants into the groundwater and underlying aquifers. Leaching can be virtually eliminated or reduced by construction of an impermeable layer at the bottom of the landfill.

Competency 0013
Apply knowledge of chemistry concepts.

13. Which of the following substances is classified as a heterogeneous mixture?

  1. sand
  2. non-fat milk
  3. iodine
  4. table salt
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Correct Response: A. A mixture consists of multiple substances that are not chemically combined. In the case of a heterogeneous mixture, the substances are not incorporated evenly, and the mixture has a non-uniform composition with clearly identifiable components, each of which having separate properties.

Competency 0014
Apply knowledge of physics concepts.

14. Two objects have charges of q subscript 1 and q subscript 2 respectively and are separated by a distance of 2 m so that they experience a force of magnitude F. The situation changes so that the distance between the objects is reduced to 1 m, and the charge of the first object is doubled. Which of the following expressions best represents the electric force between the two objects in the new situation?

  1. 2F
  2. 4F
  3. 8F
  4. 16F
Enter to expand or collapse answer.Answer expanded
Correct Response: C. Coulomb's law can be used to quantify the force between two charged objects using the equation F equals open parens K sub e Q sub 1 Q sub 2 close parens over open parens r squared close parens in which F is the force between the two charges, Q sub 1 and Q sub 2 are the values representing the amount of charge in each particle, r is the distance between the particles, and K sub E is Coulomb's constant. In this example, the distance is reduced by half and the charge on one of the objects is doubled, so these relative values can be used to determine the change in force by using the equation F equals 1 times 2 over 0.5 squared equals 2 over 0.25 equals 8 F.

Competency 0015
Apply knowledge of biology concepts.

15. Woodpeckers live and breed in deciduous forests and feed on nuts, berries, and insects. Which of the following density-independent factors would affect the carrying capacity of a population of woodpeckers in a forest ecosystem?

  1. introduction of blue jays, which are competitors for nuts and insects
  2. drought conditions resulting in a decrease in forest insect populations
  3. availability of decayed trees that can be used as suitable nesting sites
  4. predation by domestic cats associated with homes bordering the forest
Enter to expand or collapse answer.Answer expanded
Correct Response: B. Carrying capacity is the maximum number of individuals in a species that an environment can support, given current conditions. The carrying capacity of a given population is the result of the interaction of density-dependent and density-independent factors. Density-independent factors, such as weather and climate, affect a population in a given location regardless of that population's size. Here, part of the woodpecker's food source has been limited due to weather, which in turn decreases the carrying capacity of the area.