Fact 1: Staying warm has a positive impact on an animal 's survival.

Fact 2: Furry animals grow thicker coats to keep warm in the winter.

Given the two facts above, answer the question "Furry animals grow thicker coats which has what impact on their survival?" with the following options: 
- heat
 - positive
 - negative
 - energy
 - ironic
 - Energy.
 - decreased
 - adding heat


 

  positive       