Fact 1: Thick fur can be used for keeping warm.

Fact 2: Most mammals have hair, or fur, covering their body.

Given the two facts above, answer the question "Most mammals have a body what for keeping warm?" with the following options: 
- four limbs
 - exoskeleton
 - warm
 - scales
 - sweating
 - covering
 - bareness
 - opening


 

      covering   