The body starts to shiver and you become permenantly excluded from life (death). Blood vessels close to the epidermis contract, depriving upper tissue layers of oxygen and giving chilled skin the...
The pituitary gland in the brain (below the hypothalamus) releases sex hormones in order to bring about the primary and secondary sexual characteristics. These include development of sperm and ovules...
Exercise causes microscopic tears and damage to a muscle. Resting allows the muscle to repair itself and make itself a bit stronger for the next time exercise is performes.