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. Given these facts, what aspect of mammals is especially important in cold climates among the following options:
- layer of body fat under skin
 - lips
 - sweat glands
 - To conserve energy
 - toes
 - food and shelter
 - It helps them survive
 - by keeping them warm


 

 layer of body fat under skin        