You are presented with the question "What aspect of mammals is especially important in cold climates?" and the following answer choices: 
- layer of body fat under skin
 - lips
 - sweat glands
 - To conserve energy
 - toes
 - food and shelter
 - It helps them survive
 - by keeping them warm

Now knowing that mammals have a layer of fat under the skin to help insulate the body and insulation is very important in a cold climate like Arkhangelsk, choose the best answer.


 

 layer of body fat under skin        