Answer: homeostasis
Step-by-step explanation:
Homeostasis is the state of equilibrium which is maintained between the internal body and the external environment. In this condition the body maintains the internal body environment constant with respect to the changes occurring in the external environment. The conditions like body temperature, metabolism, fluid balance, blood sugar levels and pH are maintained at the optimal levels in the process of homeostasis. The homeostasis helps the organisms to survive and reproduce.