You are presented with the quiz "Phytoplankton  use what to make 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 "sunlight beams down on the different types of algae". 

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


 

  sunlight beams         