Homeostasis

Homeostasis is the property of any system especially a living organism, that regulates its internal environment so as to maintain a stable, constant condition. It is the tendency or ability of an organism or a cell to maintain internal equilibrium by adjusting its physiological processes. Body temperature in mammals, for example, is regulated by a sensor that contains the cells within the hypothalamus of the brain, sweating to reduce temperature.

read more.....
http://www.wonderwhizkids.com/index.php/properties-of-life