In the integumentary system, what is the primary function of the arrector pili muscle associated with hair follicles?

In the integumentary system, contraction of the piloerector (arrector pili) muscle produces which visible effect on the skin?

Follicles that give rise to eyebrows remain active longer than follicles of the scalp.

Keratin is found in hair and nails.

Terminal hair is located in all of the following areas EXCEPT the __________.