问题 选择题

下表是南极海洋生态系统中海水和一条食物链上几种生物体内的DDT含量,其中存在的食物链可能是(  )

名称海水生物A生物B生物C生物D生物E
DDT含量(μg/mL)0.000050.50.00520.0475.5

A.A→B→C→D→E

B.B→D→A→C→E

C.E→C→A→D→B

D.B→A→D→C→E

答案

在生态系统中,不同生物之间由于吃与被吃的关系而形成的链状结构叫做食物链.食物链起始环节是生产者.生物富集作用是指环境中一些有毒物质(如重金属、化学农药等),通过食物链在生物体内不断积累的过程.因为这些有毒物质具有化学性质稳定、不易分解的特点,会在生物体内积累而不易排出,所以随着营养级的升高而不断积累,危害最大的是这一食物链的最高级消费者.由表可知,该生态系统中存在的一条食物链是:B→D→A→C→E.

故选:B.

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