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 cyclirel:ye +xcy64 ng of carz(b.t 1r*abhalkji,d8 ly 46r bon from the atmosphere to other carbon sinks.
,*la rjba.d k(t8hr1i6y4 zbl
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 used to form carbon compounds through the pro,e;k bl9ozsurqsc,awal* :o)h+e g98 cess of photosynthesis. Heat (Option A) is a form of energy thatcl r)blh o 9zu ;+,s8kwe*a,a:segoq9 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.
| 
