Fact 1: Eyes are used for seeing by animals by sensing light.

Fact 2: Mammals are animals with a backbone.

Given the two facts above, answer the question "What do mammals use eyes for?" with the following options: 
- to sense sound
 - to touch things
 - focusing a lens
 - it needs them
 - encoded information
 - to sense light
 - to sense smell
 - food and shelter


 

      to sense light   