A) water vapor
B) oxygen
C) methane
D) ozone
2. Which molecule does not occur naturally?
A) ozone
B) methane
C) carbon dioxide
D) CFCs and HFCs
3. Which is a natural source of carbon dioxide?
A) photosynthesis
B) volcanic activity
C) fossil fuel combustion
D) ultraviolet radiation
4. Which is an anthropogenic source of carbon dioxide?
A) photosynthesis
B) volcanoes
C) fossil fuels
D) anaerobic bacteria
5. Which is a sink for carbon dioxide?
A) photosynthesis
B) ultraviolet radiation
C) soil bacteria
D) volcanoes
6. Which is a natural methane source?
A) photosynthesis
B) volcanoes
C) fossil fuels
D) anaerobic bacteria
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, 7. Which is a methane sink?
A) photosynthesis
B) ultraviolet radiation
C) the oceans
D) rainfall
8. Which is a water-vapor source?
A) evaporation
B) condensation
C) ultraviolet radiation
D) rainfall
9. Which is a water-vapor sink?
A) evaporation
B) condensation
C) ultraviolet radiation
D) fossil fuels
10. Which is an ozone source?
A) photosynthesis
B) evaporation
C) ultraviolet radiation
D) aerosols
11. Which is an ozone sink?
A) photosynthesis
B) condensation
C) ultraviolet radiation
D) fossil fuels
12. Which is a nitrous oxide source?
A) photosynthesis
B) condensation
C) ultraviolet radiation
D) soil bacteria
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, 13. Which is a nitrous oxide sink?
A) photosynthesis
B) condensation
C) ultraviolet radiation
D) soil bacteria
14. Which is a CFC source?
A) human activity
B) condensation
C) ultraviolet radiation
D) soil bacteria
15. Which is a CFC sink?
A) photosynthesis
B) condensation
C) ultraviolet radiation
D) soil bacteria
16. Clouds are composed of __________.
A) water vapor
B) aerosols
C) nitrogen
D) CFCs
17. Ninety-nine percent of the atmosphere is found below __________ kilometers.
A) 32
B) 100
C) 170
D) 200
18. At sea level there is/are __________ kilogram(s) per square centimeter of air pressure
on average.
A) 1
B) 2
C) 3
D) 4
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