What does homeostasis refer to in a biological context?

Homeostasis refers to the mechanisms that living organisms employ to maintain a stable internal environment despite changes in external conditions. This process is crucial for the survival of organisms, as it ensures that key parameters such as temperature, pH, hydration, and ion concentration remain within a range that supports proper functioning.

For instance, humans regulate their body temperature through mechanisms like sweating or shivering to maintain a temperature conducive to metabolic processes. Similarly, plants can adjust their stomatal openings to regulate water loss and gas exchange, thereby contributing to homeostasis.

In contrast, the other options do not correctly describe homeostasis. The process of gas exchange pertains specifically to the diffusion of oxygen and carbon dioxide, which is vital for respiration but not the overarching concept of maintaining internal equilibrium. The productivity of living organisms refers to the rate of energy capture (like photosynthesis) and how efficiently organisms convert energy, rather than their internal balance. Lastly, cellular respiration is the process by which cells convert nutrients into energy, not directly related to the broader concept of maintaining a stable internal environment.