What term describes the body's ability to maintain a stable internal environment despite external changes?

The term that describes the body's ability to maintain a stable internal environment despite external changes is "homeostasis." This concept is crucial in understanding how living organisms function optimally in varying conditions. Homeostasis involves complex physiological processes that regulate factors such as temperature, pH, hydration, and electrolyte balance, ensuring that the internal conditions remain relatively constant even when external conditions fluctuate.

This maintenance of equilibrium is vital for the survival of organisms, as it allows them to thrive in diverse environments. For example, when the body temperature rises due to heat exposure, mechanisms such as sweating and increased blood flow to the skin are activated to cool the body down, thereby preserving homeostasis.

In contrast, metabolism refers to the biochemical processes that occur within the body to convert food into energy, immunity pertains to the body's defense mechanisms against pathogens, and adaptation refers to the evolutionary changes over time that organisms undergo in response to their environment. While all these concepts are interconnected in the broader context of physiology, homeostasis specifically addresses the immediate regulatory processes that uphold the internal balance essential for health and normal functioning.