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

Fact 2: Sheep are mammals with thick, woolly fur, and hoofed feet.

Given the two facts above, answer the question "what can be used for keeping warm?" with the following options: 
- hats
 - carbon molecules
 - sheep
 - clouds
 - protein
 - hair
 - keratin
 - ice cubes


 

   sheep      