A. our share of resources B. a biological creature C. a given area D. the maintenance of the ecosystem E. the source of food F.

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问题 A. our share of resources B. a biological creature
C. a given area D. the maintenance of the ecosystem
E. the source of food F. various species
Plants are essential in an ecosystem because to other living creatures they are______.

选项

答案E

解析根据第三段第一句话“Plants make up the biggest group of biological creatures within anecosystem，and that’s because they are the natural food producers for everyone．”可知，植物是有生命的生物的食物来源，所有它们对生态系统很重要，所以本题选E。

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本试题收录于：职称英语理工类C级题库职称英语分类