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.

B) sweat glands have special channels through the skin

Explanation:

The human skin has special channels called the pores through which water and oil passes through. The pores are opening of the hair follicles on the skin.It serves as an important osmoregulatory method by the body. The sweat helps to cool off the skin when there is heat.

blue stars have the highest surface temp

stellar distances are usually expressed in light-years

the measure of a star's brightness is called magnitude

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