Homeostasis is life's ability to stay balanced, when the environment changes. Animals keep their body in a stable condition. They do so by regulating their inner equilibrium . For example, they adjust their pH, temperature, amount of oxygen or carbon dioxide in the blood and so on. In living things, the study of how they keep in a stable condition is called physiology. Mostly, our physiology works unconsciously throughout life. We have many negative feedback systems which adjust our physiology so that we stay alive. These systems are self-organising and do not need to be learnt. They are inherited.