Q: What sound can be heard when sound waves bounce back from a hard object?


Read this paragraph and choose the correct option from the provided answers:

Did you ever hear an echo of your own voice? An echo occurs when sound waves bounce back from a hard object. The man in Figure below is trying to create an echo by shouting toward a rock wall. When the sound waves strike the rock wall, they can’t pass through. Instead, they bounce back toward the man, and he hears an echo of his voice. An echo is just one example of how waves interact with matter.

 Choices:

- loop

- eerie

- boom

- echo


A:
echo