In a balanced ocean environment which animal has the largest population?

a. shark
b. fish
c. plankton

Sharks play a very important role in the oceans in a way that an average fish does not. Sharks are at the top of the food chain in virtually every part of every ocean. In that role, they keep populations of other fish healthy and in proper proportion for their ecosystem

In a balanced ocean enviorment plankton has the largest population

That would be a working theory.