Infrared rays clog the sweat pores.
There is not enough of the pigment melanin (produced by the melanocytes) to filter the ultraviolet rays from the sun.
The blood vessels become irritated by the amount of heat.
The epidermis is unable to tan.
Wrinkling of the skin, leathery thickening of the skin, and wartlike lumps.
Discolouration of fingernails, wrinkling of the skin, and spread of fungus in the skin.
Shrinking blood vessels in the face, thinning of the skin, and wartlike lumps.
It had not been discovered yet.
There was little exposure to the sun.
Pale skin was considered a sign of beauty.
B & C
All of the above.