Content Benchmark E.12.A.2
Students know the composition of Earth’s atmosphere has changed in the past and is changing
today. I/S
Sample Test Questions
1st Item Specification: Explain how variations in the ozone layer affect the amount of
ultraviolet radiation entering the Earth’s atmosphere.
Depth of Knowledge Level 1
1. Ozone helps prevent ultraviolet radiation (UV) from reaching Earth’s surface by
A. reflecting UV back into space.
B. diffracting UV into the ionosphere.
C. absorbing UV into its molecular structure.
D. converting UV into gamma rays.
2. Products containing halocarbons can deplete the ozone layer and result in increased levels of
ultraviolet radiation reaching Earth’s surface. Which of the following has NOT been a
source of halocarbons?
A. Yard wastes
B. Automobiles
C. Air conditioners
D. Refrigerators
Depth of Knowledge Level 2
3. Use the diagram to answer the following question.
(From http://www.esrl.noaa.gov/gmd/infodata/faq_cat-2.html)
CFCs increase the amount of ultraviolet radiation reaching Earth because they
A. prevent ozone from forming near Earth’s surface.
B. deplete the amount of ozone in the stratosphere.
C. are absorbed into the Sun, where they change into ultraviolet radiation.
D. form a layer around Earth, acting like a lens which increases radiation.
4. Use the diagram to answer the following question.
(From http://www.climatescience.gov/Library/sap/sap2-4/public-review-draft/sap2-4-prd-ch3.pdf)
Which statement most accurately interprets the data presented on the graph?
A. Ozone levels steadily decrease while UV levels steadily increase.
B. Ozone levels steadily increase while UV levels steadily decrease.
C. Minor increments in percent of ozone and UV occur over time.
D. Sharp decreases in ozone are mirrored by sharp increases in UV.
2nd Item Specification: Describe how life forms have affected the composition of the
atmosphere over time.
Depth of Knowledge Level 1
5. Earth’s early atmosphere gained oxygen through photosynthesis and
A. cellular respiration.
B. photochemical dissociation.
C. organic decomposition.
D. nitrogen fixation.
6. The two most abundant greenhouse gases in Earth’s atmosphere are
A. water vapor (H2O) and carbon dioxide (CO2).
B. carbon dioxide (CO2) and methane (CH4).
C. ozone (O3) and carbon monoxide (CO).
D. nitrogen (N2) and oxygen (O2).
Depth of Knowledge Level 2
7. The term “anthropogenic emissions” refers to greenhouse gases released into the atmosphere
as a result of human activities. Use the diagram to answer the following question.
(From http://www.eia.doe.gov/oiaf/1605/ggccebro/chapter1.html)
Which statement is an accurate interpretation of the graph?
A. Atmospheric concentrations of CO2 have steadily decreased as anthropogenic
emissions have steadily increased.
B. Before 1850, humans were releasing so much CO2 into Earth’s atmosphere that the
values won’t even fit on the scale of this graph.
C. There is absolutely no correlation between anthropogenic emissions and
atmospheric concentrations of CO2.
D. Since the 1960s, atmospheric concentrations of CO2 have risen at a rate
approximately equal to that of anthropogenic emissions.
8. Cyanobacteria first appeared in Earth’s oceans over 2 billion years ago, and were extremely
abundant by 545 million years ago. Cyanobacteria affected Earth’s atmosphere by
A. rapidly increasing carbon dioxide levels in the atmosphere.
B. gradually adding to the amount of oxygen in the atmosphere.
C. slowly consuming all the ozone from the atmosphere.
D. progressively using up the nitrogen in the atmosphere.
3rd Item Specification: Describe how natural events have affected the composition of the
atmosphere over time (e.g., volcanoes and meteorites).
Depth of Knowledge Level 1
9. The two sources which contributed significant quantities of gases to Earth’s early atmosphere
were volcanic outgassing and
A. sublimation and thawing of Earth’s ice caps.
B. widespread burning of the plant matter in Earth’s forests.
C. ejection of gaseous matter from a nearby supernova.
D. comets impacting Earth, releasing gases as they vaporized.
10. Certain atmospheric gases are thought of as “non-variable” because their abundance remains
unchanged over vast periods of time. The two gases with the longest residence time in
Earth’s atmosphere are
A. nitrogen (N2) and oxygen (O2).
B. carbon dioxide (CO2) and methane (CH4).
C. carbon monoxide (CO) and chlorine (Cl2).
D. ozone (O3) and hydrogen (H2).
Depth of Knowledge Level 2
11. Of the following, which provides evidence that Earth’s atmosphere was altered from that of a
reducing atmosphere to an oxidizing atmosphere?
A. Volcanic outgassing poured vast quantities of water vapor into the atmosphere.
B. Levels of carbon dioxide have steadily increased over the past several decades.
C. Sediments rich in iron (III) oxide have been layered in thick deposits across Earth.
D. The majority of hydrogen and helium has escaped Earth’s atmosphere into space.
12. Use the diagram to answer the following question.
(From http://smallcomets.physics.uiowa.edu/faq.htmlx)
Which statement most accurately explains how frozen water in comets is added to Earth’s
atmosphere?
A. The comets strike the oceans and melt, then evaporate into the atmosphere.
B. As comets vaporize, they cause precipitation which falls into the atmosphere.
C. Descending water vapor from the comets is mixed by wind into the atmosphere.
D. Ice crystals from comet break up are scattered throughout the atmosphere as snow.
Content Benchmark E.12.A.2
Students know the composition of Earth’s atmosphere has changed in the past and is changing
today. I/S
Answers to Sample Test Questions
1. C, DOK level 1
2. A, DOK level 1
3. B, DOK level 2
4. D, DOK level 2
5. B, DOK level 1
6. A, DOK level 1
7. D, DOK level 2
8. B, DOK level 2
9. D, DOK level 1
10. A, DOK level 1
11. C, DOK level 2
12. C, DOK level 2