The outer layers of human skin are composed of dead cells impregnated with keratin and oil, which make the epidermis relatively impermeable to water, yet humans sweat freely in hot temperatures. This occurs because:

The question is incomplete. The complete quesetion is:

The outer layers of human skin are composed of dead cells impregnated with keratin and oil, which make the epidermis relatively impermeable to water, yet humans sweat freely in hot temperatures. This occurs because:

a) the salt in sweat allows it to diffuse through the skin.

b) sweat glands have special channels through the skin.

c) an osmotic gradient in sweat moves it through the skin.

d) sweating occurs in only those areas of the body where the skin is water permeable.

Answer:

b) sweat glands have special channels through the skin.

Explanation:

Sweat glands are present in the reticular region of the dermis. This part of the dermis contains bundles of thick collagen fibers, fibroblasts, and various cells. Sweat glands are present between these fibers. The ducts of sweat glands open on the tops of the epidermal ridges as sweat pores to release the secretions of the gland outside. This is how irrespective of the presence of the keratin layer on the outer surface of the skin, it releases sweat in hot summer days.