Question 1
Which process removes carbon dioxide from the air?
- Respiration
- Combustion
- Photosynthesis
- Decomposition
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Answer: C (1)
Question 2
Describe how carbon in the bodies of dead plants returns to the air as carbon dioxide, and how carbon in dead organisms that are buried for millions of years may later return to the air.
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- decomposers / bacteria and fungi break down the dead plants (1)
- decomposers respire (1)
- releasing carbon dioxide (into the air) (1)
- buried organisms form fossil fuels / coal, oil, gas (1)
- burning / combustion of the fossil fuel releases carbon dioxide (1)
- Max 4
Question 3
A student states that the amount of carbon dioxide in the air stays roughly constant in a natural ecosystem. (a) Name the process that removes carbon dioxide from the air. [1] (b) Name two processes that add carbon dioxide to the air. [2]
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- (a) photosynthesis (1)
- (b) any two from: respiration; combustion / burning; decomposition / decay (2)
- ignore breathing