题目选项分析

Lacking an understanding of the earth's massive and complex ecosystem, many people tend to overestimate the importance of organisms at or near the top of the food chain, such as human beings, and underestimate that of micro-organisms near the bottom of the food chain, such as plankton

Lacking an understanding of the earth's massive and complex ecosystem, many people tend to overestimate the importance of organisms, such as human beings, that are at or near the top of the food chain, and underestimate it when micro-organisms, such as plankton, dwell near the bottom of the food chain