Head hair is especially important in preventing heat loss from the body, and insulation serves to both prevent heat loss in the winter and heat gain in the summer. Given these facts, what is a form of natural insulation that humans have among the following options:
- fur and fat
 - Fire
 - Blankets
 - Animal fur
 - Head hair
 - layers of fat
 - Clothes
 - copper


 

     Head hair    