16.To appreciate fully the diversity andabundance of life in the sea，it helps to think small．

(特殊结构it helps to…做…有帮助)

要充分认识海洋生命的多样性和丰富性，从小的角度思考有帮助。

目的状语：Toappreciate fully the diversity and abundance of life in the sea,

主句：it helpsto think small．（这里的it是形式主语，没有实际意义）