Study Guide

Field 108: Earth Science 
Sample Selected-Response Questions

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General Test Directions

This test consists of two sections: 1) a section with selected-response questions and 2) a constructed-response section.

Each question in the first section is a selected-response question with four answer choices. Read each question and answer choice carefully and choose the ONE best answer.

Try to answer all questions. Even if you are unsure of an answer, it is better to guess than not to answer a question at all. You will NOT be penalized for guessing.

The second section of this test consists of one constructed-response assignment. You will be asked to provide a written response to the assignment. Directions for completing your written response to the constructed-response assignment appear immediately before the assignment.

You may NOT use any type of calculator or reference materials during the test session.

Sample Selected-Response Questions

Competency 0001 
Apply knowledge of scientific practices and techniques to earth science investigations.

1. An earth science teacher provides students with access to a virtual lab that allows them to track changes in the temperature of seawater over space and time. The goal of this investigation is to explore one pathway by which changes in the temperature of seawater due to global climate change affect a marine ecosystem. Which of the following additional data would best allow students to achieve the goal of this investigation?

  1. location and dates of major coral bleaching events around the world
  2. changes in tonnage of commercial fish catches for various fisheries
  3. rate of population increase of invasive marine lionfish in southeast U.S. waters
  4. location and size of new grey seal colonies along the northeast U.S. coast

Correct Response: A. Corals have a mutualistic relationship with photosynthetic algae, called zooxanthellae, that live within the coral tissues. The zooxanthellae are provided with a protected environment within the coral and, in return, the zooxanthellae provide the coral with oxygen and nutrients, and are responsible for the bright color of corals. An increase in water temperature, however, causes the zooxanthellae to be expelled from the coral, turning the coral white in a process known as coral bleaching. This process often leads to the death of the coral.

Competency 0004 
Apply crosscutting concepts to earth science concepts, processes, and phenomena.

2. Which of the following factors would be most likely to destabilize thermohaline circulation in the North Atlantic Ocean?

  1. warming of the lower atmosphere over the equatorial ocean
  2. increased summer melting of the sea ice covering the Arctic Ocean
  3. influx of fresh water from melting of the Greenland ice sheet
  4. increased number and intensity of hurricanes and other storms

Correct Response: C. Thermohaline circulation in the North Atlantic Ocean involves the large-scale flow of upper, less dense surface waters northward toward Greenland and the Arctic. As the water cools and becomes denser, it sinks below the surface and moves southward. Increased Greenland meltwater would dilute the surface current, decreasing the water's density and destabilizing the thermohaline circulation pattern.

Competency 0006 
Apply knowledge of stellar characteristics.

3. The slow shrinking of a star's solar core due to nuclear fusion results from which of the following conditions?

  1. increasing core temperature
  2. decreasing warping of gravity
  3. increasingly active core convection currents
  4. decreasingly dense elemental composition

Correct Response: A. In a star's core, the conversion of hydrogen into helium by way of nuclear fusion continues until there is no more hydrogen in the star's core. At this point, the core begins collapsing due to gravitational forces. This collapse increases the pressure and temperature of the star's core.

Competency 0008 
Apply knowledge of the earth, moon, and sun system.

4. Which of the following observations provides the best evidence for the giant-impact hypothesis for the origin of the earth's moon?

  1. The earth's moon is much larger in size than the moons of Mars and Mercury.
  2. Analysis of lunar rocks shows that the moon was largely molten at one time.
  3. Frozen water has been found in deep valleys and under the surface of the moon.
  4. Analysis of maria rocks shows that they are composed of basalt from the moon's interior.

Correct Response: B. The giant-impact hypothesis suggests that the earth's moon was formed from the debris that resulted when an astronomical body collided with the earth billions of years ago. As a result of this collision, part of earth's mantle was ejected and this molten material eventually clumped together to form the moon. The inclusion of the earth's molten mantle in the moon's formation is reflected by moon rocks composed of similar molten material.

Competency 0009 
Apply knowledge of the history of the earth.

5. Massive configurations of banded iron rocks were formed from 1 point 8 to 2 point 5 billion years ago during the Proterozoic. The presence of these sediments indicates that:

  1. undersea hydrothermal vents were releasing large quantities of iron.
  2. segregation of iron into the inner and outer core of the earth had not yet occurred.
  3. corrosive acids were present in large quantities in the early atmosphere and hydrosphere.
  4. concentrations of oxygen in seawater were rising due to photosynthesis by cyanobacteria.

Correct Response: D. Earth's primitive atmosphere contained little free oxygen, so iron released into ocean waters as a result of the weathering of iron-containing rocks remained in the form of iron ions. With the appearance of cyanobacteria capable of photosynthesis, however, iron ions combined with free oxygen to form iron oxide. This compound precipitated out of solution and formed a layer on the ocean floor. Over time, variations in the levels of free oxygen resulted in alternating periods of iron oxide formation.

Competency 0010 
Apply knowledge of plate tectonics.

6. Ridge push and slab pull are two types of forces related to plate movement. Compared with ridge push, slab pull is:

  1. associated with much more severe normal faulting.
  2. a greater contributor to the forces producing plate movement.
  3. associated with mountain building over a much wider area.
  4. a more direct consequence of the movements of convection currents.

Correct Response: A. Slab pull occurs at subduction zones where the older plate edges, which are cooler and thus denser, sink and pull the rest of the plate along as they move downward. Plates that have many such large subducting edges tend to move more rapidly than those driven primarily by ridge push.

Competency 0013 
Apply knowledge of the relationship between water and atmospheric processes.

7. Which of the following statements best describes the significance of the latent heat of water to energy transfer in Earth systems?

  1. The transfer of energy by currents running from warm equatorial ocean waters to higher latitude waters depends on differences between the two in latent heat.
  2. The high latent heat of water leads to warmer winter temperatures for coastal regions than winter temperatures in the interiors of continents.
  3. Prevailing winds blow from regions where the latent heat of water vapor in the air is high to regions where the latent heat of water vapor is low.
  4. The input of latent heat required to effect the phase change of liquid water is stored in water vapor and fuels storms when it is released as the vapor cools back into a liquid.

Correct Response: D. The latent heat of water refers to the heat absorbed or released by water as it changes state. This latent heat is transported to different areas of the earth as the result of movement of the earth's atmosphere. When storms occur and water vapor is changed to the liquid state, water molecules release energy equivalent to the amount associated with the process of evaporation, which moves water molecules from bodies of water and living organisms to the atmosphere.

Competency 0015 
Analyze the hydrologic system, freshwater, and ocean characteristics.

8. Recently, scientists have been able to measure the rate of flow of glaciers covering Greenland and have found that the ice is moving toward the sea at a much higher rate than previously thought possible. Which of the following statements provides the best explanation for this phenomenon?

  1. Rising sea levels dissolve the edges of the glaciers, which are quickly replaced by inland ice.
  2. Heavier winter snowfalls on inland ice fields increase the weight of the ice, raising the pressure and forcing the glaciers to move.
  3. Higher ambient temperatures increase the rate of sublimation from the surface of the glaciers, making them lighter and easier to move.
  4. Increased meltwater due to higher ambient temperatures bores holes in the glacial ice allowing water to reach bedrock and act as a lubricant.

Correct Response: D. Satellite data, used to monitor the movement of glaciers in Greenland, indicates that glacier velocity has increased in recent years. This change in velocity is thought to be associated with increased surface air temperatures which, in turn, increase the amount of meltwater reaching the glacial bed. This extra water allows the glacier to move more rapidly over underlying rock surfaces.

Competency 0016 
Apply knowledge of natural hazards and processes and their impact on human societies.

9. Which of the following major greenhouse gases contributes the most to overall global climate change?

  1. methane
  2. water vapor
  3. ozone
  4. carbon dioxide

Correct Response: B. Water vapor in the earth's atmosphere contributes more directly to the greenhouse effect than methane, ozone, or carbon dioxide. Specifically, water vapor in the form of clouds, fog, and other forms of atmospheric haze absorbs longwave radiation and reflects it back to earth. Additionally, warming of the earth's surface causes an increase in the evaporation rates and an associated increase in moisture in the earth's atmosphere, which results in a positive feedback loop.

Competency 0019 
Apply knowledge of monitoring and changing human impacts on Earth systems.

10. In the United States, the largest anthropogenic source of mercury pollution in the environment comes from:

  1. automobile exhaust.
  2. application of paints and solvents.
  3. coal-fired power plant emissions.
  4. leakage from municipal landfills.

Correct Response: C. Coal contains mercury, an element that occurs naturally within the earth's crust. When coal is burned as an energy source in power plants, any mercury that it contains is released into the atmosphere. Atmospheric mercury is eventually transported back to the ground by way of dry deposition or as a component of various forms of precipitation.