Question

the arrector pili muscles predominate, useful function in humans is to

assist in the release sebum from nearby sebaceous glands

prevent germs from entering the hair shaft

provide warmth by making the hair stand on end

stimulate faster hair growth

Explanation:

The arrector pili muscle is attached to hair follicles. When it contracts, it causes hair to stand up. In humans, this action helps in the release of sebum from nearby sebaceous glands. Sebum lubricates the skin and hair. While in some animals hair - standing can provide warmth (by trapping air), in humans this is not very effective. There is no evidence that it prevents germs from entering the hair shaft or stimulates hair growth.

Answer:

assist in the release sebum from nearby sebaceous glands