When man eats fish which feeds on zooplanktons which have eaten...

A food chain is a linear sequence of organisms through which nutrients and energy pass as one organism cats another. The food chain is represented as: Small plants $\rightarrow$ zooplanktons $\rightarrow$ Fish $\rightarrow$ Man Primary Producer $\rightarrow$ Primary consumer $\rightarrow$ Sccondary consumer $\rightarrow$ Tertiary consumer Related Theory