You are presented with the quiz "What requires great amounts of water to use their gills to extract dissolved oxygen?" 

But you don't know the answer, so you turn to your teacher to ask for hints. He says that "an aquatic animal requires great amounts of water to survive" and "fish can survive in water by using their gills to extract the dissolved oxygen". 

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


 

    aquatic animals       