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

Fact 2: Sounds are vibrations in air.

Given the two facts above, answer the question "Vibrations in air can be used for what by animals?" with the following options: 
- activation energy
 - communication
 - Something to move
 - sleeping
 - sustenance
 - Heart rate
 - food and shelter
 - tasting


 

  communication       