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