Fact 1: Hearing is used for sensing sound by animals.

Fact 2: Hearing requires functioning ears.

Given the two facts above, answer the question "What are used for sensing sounds by animals?" with the following options: 
- ears
 - echolocation
 - birds
 - fibers
 - toads
 - the nose
 - Frogs.
 - the blood


 

 ears        