You are presented with the quiz "What does plant plankton need for food?" 

But you don't know the answer, so you turn to your teacher to ask for hints. He says that "phytoplankton are bacteria and algae that use sunlight to make food" and "phytoplankton, or plant plankton, needs sunlight to live, the same way plants on land do". 

So, what's the best answer to the question?


 

 Sunlight          