You are presented with the question "What can be used by an animal to keep warm?" and the following answer choices: 
- a thick pelt
 - heat energy
 - evaporation
 - energy
 - kinetic energy
 - electricity
 - four limbs
 - organic molecules

Now knowing that thick fur can be used for keeping warm and pelts are the skins of animals with the fur attached, choose the best answer.


 

 a thick pelt        