Rheostasis refers to the ability of an organism to maintain a stable and constant internal environment despite external changes. Synonyms for the term include homeostasis, hormonal regulation, and physiological balance. Some other terms that could be used to describe rheostasis might be environmental acclimation, adaptive response, or metabolic control. These terms all describe the ability of an organism to respond to changes in its surroundings and maintain its own internal state. The concept of rheostasis is important in biology and physiology, as it helps scientists understand how living organisms are able to survive in vastly different environments, and how they are able to adapt and evolve over time.