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

Fact 2: Otters fur is the thickest fur of any animal.

Given the two facts above, answer the question "what can be used to make clothing for keeping warm?" with the following options: 
- cellulose
 - bamboo
 - heat
 - fibrous
 - otters
 - energy
 - chemicals
 - Loose


 

     otters    