Fact 1: Mammals have a layer of fat under the skin to help insulate the body.

Fact 2: Hair is used to insulate and keep the body warm in a large variety of climates.

Given the two facts above, answer the question "Mammals have a layer of fat under the skin to help keep the body warm in what?" with the following options: 
- cozy cabins
 - by keeping them warm
 - warm areas
 - a variety of climates
 - In the winter
 - heat or cold
 - the environment
 - sunny places


 

    a variety of climates     