You are presented with the quiz "Doing what with sound waves off the bottom of the ocean is used to find the location of objects?" 

But you don't know the answer, so you turn to your teacher to ask for hints. He says that "sonar is used to find the location of an object" and "sonar bounces sound waves off the bottom of the ocean". 

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


 

       bouncing them    