Fact 1: Sound can be used for communication by animals.

Fact 2: Animals use both ears to localize sound.

Given the two facts above, answer the question "What do animals utilize to localize sound?" with the following options: 
- feet
 - toes
 - hands
 - four limbs
 - hormones
 - nervous system
 - Their Ears
 - heat energy


 

       Their Ears  