Carbon Cycle Quiz
Questions: 16 · 10 minutes
1. Methane released from a wetland does not necessarily remain methane indefinitely. What can happen to it in the atmosphere?
It can only return unchanged to the wetland
It immediately becomes solid carbonate rock
It is converted into nitrogen through photosynthesis
It can be oxidized, eventually producing carbon dioxide
2. A rabbit eats grass. What is the most direct carbon transfer taking place?
Carbon moves from plant biomass into animal biomass
Carbon moves from animal biomass into rock
Carbon moves from the atmosphere directly into the rabbit without food
Carbon moves from soil minerals into sunlight
3. Which reservoir contains much more carbon than the atmosphere and exchanges carbon with it at the surface?
Freshwater rivers
Living land animals
Clouds
The oceans
4. Atmospheric carbon dioxide often declines during Northern Hemisphere spring and summer. What is the main carbon-cycle explanation?
Volcanic activity stops during these seasons
Growing vegetation removes more carbon dioxide through photosynthesis
Fossil fuels naturally reform in shallow soils
Ocean carbon is converted entirely into marine animals
5. A volcanic eruption releases carbon dioxide that originated within Earth. Which pathway does this illustrate?
Atmosphere to biosphere
Ocean to soil
Geosphere to atmosphere
Biosphere to hydrosphere
6. A fallen tree decays on a forest floor. Which carbon transfer is most directly associated with decomposers acting on the wood?
Carbon from biomass enters decomposers, soil, and the atmosphere
Carbon moves from ocean water into marine shells
Carbon moves from the atmosphere into fossil fuels immediately
Carbon in the wood is transformed into nitrogen
7. A large forest is cleared and burned. Which combined effect is most likely?
Less carbon uptake by trees and more carbon released through combustion
More carbon storage in trees and no effect from burning
More photosynthetic uptake and less atmospheric carbon dioxide
Faster formation of carbonate rock and lower ocean carbon
8. Which situation is most likely to store carbon on a geological timescale?
An animal exhales after eating
Leaves grow during spring
Carbon-rich sediment is buried and eventually forms sedimentary rock
Surface seawater releases carbon dioxide during warming
9. During cellular respiration, what commonly happens to carbon contained in sugars?
It is converted entirely into soil minerals
Some of it is released as carbon dioxide
It becomes nitrogen gas
It permanently remains in the organism
10. Why does fossil-fuel combustion disrupt the modern carbon cycle?
It transfers atmospheric carbon into rocks faster than natural burial
It prevents organisms from carrying out respiration
It removes carbon from the cycle permanently
It rapidly transfers long-stored geological carbon into the atmosphere
11. When coal is burned in a power plant, which major carbon transfer occurs?
From the atmosphere to the ocean
From living biomass to soil only
From a geological reservoir to the atmosphere
From carbonate rock to plant tissue
12. Which process directly removes carbon dioxide from the atmosphere and incorporates its carbon into plant tissue?
Combustion
Cellular respiration
Decomposition
Photosynthesis
13. Which pairing correctly identifies a carbon reservoir and a carbon flux?
Forest biomass is a reservoir; photosynthesis is a flux
Photosynthesis is a reservoir; the atmosphere is a flux
Respiration is a reservoir; ocean water is a flux
Combustion is a reservoir; soil carbon is a flux
14. A farmer repeatedly tills carbon-rich soil, increasing its exposure to oxygen. What outcome is most likely?
Decomposition stops because microbes cannot use oxygen
Faster decomposition can increase carbon dioxide release
All soil carbon becomes plant biomass
Atmospheric carbon is instantly locked into bedrock
15. When additional carbon dioxide dissolves in seawater, which chemical change can follow?
The water loses all dissolved carbon
Carbonic acid forms, contributing to a decrease in pH
Carbon dioxide changes directly into oxygen gas
The seawater becomes more alkaline because hydrogen ions disappear
16. Over long timescales, how can the weathering of silicate rocks influence atmospheric carbon dioxide?
It creates fossil fuels directly from atmospheric gases
It prevents carbon from entering rivers
It contributes to processes that ultimately transfer carbon into ocean sediments
It converts all rock carbon into methane