what is homeostasis? explain

Homeostasis, is derived from the Greek words for "same" and "steady," refers to any process that living things use to actively maintain fairly stable conditions necessary for survival.

Definition - Homeostasis, as currently defined, is a self-regulating process by which biological systems maintain stability while adjusting to changing external conditions.

If homeostasis is successful, life continues; if it's unsuccessful, it results in a disaster or death of the organism. 

Homeostasis is the state of steady internal, physical, and chemical conditions maintained by living systems. This is the condition of optimal functioning for the organism and includes many variables, such as body temperature and fluid balance, being kept within certain pre-set limits.

Examples include thermoregulation, blood glucose regulation, calcium homeostasis, potassium homeostasis, and osmoregulation.