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

Fact 2: Pelts are the skins of animals with the fur attached.

Given the two facts above, answer the question "What can be used by an animal to keep warm?" with the following options: 
- a thick pelt
 - heat energy
 - evaporation
 - energy
 - kinetic energy
 - electricity
 - four limbs
 - organic molecules


 

 a thick pelt        