Skin, be it brown, white or black, is vulnerable to exposure to various external factors. Be it the sun, rain, snow, sleet, fire or air, everything leaves its mark in some form, from very minor problems like tanning to very severe effects like burns.

According to the dictionary, skin is defined as the external covering of any living thing. In humans, it refers to the covering of the body, which is made up of layers of tissue that protect the organs and muscles beneath. It is basically composed of the epidermis, dermis and hypodermis. The epidermis is the topmost layer containing no blood vessels. The next layer is the dermis, which contains blood vessels, hair follicles, glands and lymphatic tissue, and the hypodermis attaches the skin to the underlying bone and muscle.

Skin's main functions are protection against the weather, insulation in cold climates and keeping the body cool through the process of sweating in hotter climates. It thus controls the temperature of the body. It has the ability to feel, and last but not least, it synthesizes vitamins A and D with the help of sunlight.

The pigmentation in the skin is useful in absorbing harmful radiation and contains enzymes that can reverse ultraviolet-induced damage to the skin. It is the melanin in the skin that determines the color of the skin. Another factor is the geographical location of the person. Evolution has been such that each person's body has evolved in a manner best suited to the climate of his location.