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

Fact 2: Basically, heat is energy.

Given the two facts above, answer the question "What kind of animals conserve energy with their hair or fur?" with the following options: 
- fur
 - bears
 - mammals
 - sweating
 - frogs
 - cactus
 - goats
 - humans


 

   mammals      