Fact 1: Mammals conserve body heat with their hair or fur.

Fact 2: Birds waste a lot of body heat trying to keep warm in exposed areas.

Given the two facts above, answer the question "Mammals keep what with hair or fur?" with the following options: 
- coat
 - wool
 - energy
 - nektar
 - warm
 - cold
 - shivering
 - hydrated


 

     warm    