本题目来源于试卷: IB ESS Unit 2: Ecosystems & Ecology，类别为 IB环境系统与社会
[单选题]
There is continuous cycling of carbon from the atmosphere to othe uv4brv 5vaxa) oq1.0ar carbo02 /k *l.,b qs g1rlws :im3fywvduyy*n sinks.
yu.qv1 s,g l3sy/f y lb:2*k*wm0widr
Identify the main source of energy for the carbon cycle.
A. Heat
B. Sunlight
C. Chemical energy
D. Energy from respiration
参考答案: B
本题详细解析:
Energy from the sun (Option B) is usen3z ps fag+)5id to form carbon compounds through the process of photosynthesis. Heat (Option A) is a p3)n +a5zgsi fform of energy that cannot be converted to chemical energy by living things.
Chemical energy (Option C) is held in the bonds of organic compounds which are produced by photosynthesis, or comes from hydrothermal vents deep in the oceans. Even though it is an energy source, it is not the main source of energy for the carbon cycle.
Energy stored in chemical bonds is released (Option D) during respiration which is used to power the cells processes.
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