Question

In a marine ecosystem, starfish prey upon the common mussel. Common mussels feed upon plankton. What is MOST likely to happen if the number of starfish is increased?

Answer 1

The answer is;

The numbers of mussels would reduce

Planktons population would increase.

This is a phenomenon common in food chains where a reduction in predator population increases the prey population and vice versa.  This is because the species population in a food chain/food web are interlinked and source energy from one another directly or indirectly.