Fact 1: Head hair is especially important in preventing heat loss from the body. Fact 2: Insulation serves to both prevent heat loss in the winter and heat gain in the summer. Given the two facts above, what is a form of natural insulation that humans have?

Options are: a. fur and fat; b. Fire; c. Blankets; d. Animal fur; e. Head hair; f. layers of fat; g. Clothes; h. copper;
The answer is:
e.