Answer: homeostasis
Explanation: Homeostasis is the ability of a system to maintain a balance in its internal environment. At the level of an organism, it is the set of parameters that must remain constant or adapt to the needs, such as blood pressure or heart rate, body temperature, blood glucose.
The concept of homeostasis was mentioned for the first time in 1866 by French physician and physiologist Claude Bernard. Today, the concept has been extended to other systems than purely organic ones, and can also be applied to an ecosystem.