Sweat is produced by sweat glands as a response to increased body temperature, and its evaporation from the skin helps cool the body, regulating temperature.
So, the correct option is (A): Sweat - temperature regulation
The physiological process of the elimination of metabolic waste from the body is called excretion. The excretory products comprise amino acids, carbon dioxide, urea, uric acid, water, and ammonia. Some of the Molluscs and Echinoderms excrete waste products from the body in the form of amino acids. Ammonia is the foremost excretory product in animals, it is derived from the proteins exists in the food we eat.

Read More: Excretion in Human Beings