A food chain occurring in the sea which provides food for many people can be written as :

A food chain occurring in the sea which provides food for many people can be written as : phytoplankton `to` zooplankton `to` X `to` Y (a) Name one phytoplankton. (b) Name two zooplanktons. (c) What could be X ? (d) Name the organism which Y could be. (e) Which organism in the above food chain is a (i) primary consumer, and (ii) tertiary consumer ?

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