You are presented with the quiz "Fins nearly as long as what can be used to move through water?" 

But you don't know the answer, so you turn to your teacher to ask for hints. He says that "along tail can be used to move through water by an animal" and "all thresher sharks have tail fins nearly as long as the rest of the body". 

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


 

  the rest of the body         