What is homeostasis?

Homeostasis is fundamentally about maintaining a stable internal environment in an organism despite changes in external conditions. This concept is crucial for the survival and proper functioning of living organisms. In biological systems, homeostasis involves various physiological processes and feedback mechanisms that regulate factors such as temperature, pH, hydration, and concentration of ions and nutrients.

For instance, in humans, mechanisms such as sweating or shivering help regulate body temperature, while the kidneys adjust the balance of water and electrolytes to ensure that the body's internal environment remains stable. This process is vital for cell function and overall health, as deviations from optimal internal conditions can lead to dysfunction or disease.

In contrast, the other options outline processes that contribute to biological functions but do not encapsulate the essence of homeostasis. Cell division is a vital reproductive and growth mechanism, the movement of materials across cell membranes pertains to transport processes rather than internal stability, and the development of new species relates to evolutionary change, which is separate from the concept of maintaining internal equilibrium. Therefore, recognizing homeostasis as the maintenance of a stable internal environment is essential for understanding how organisms adapt and survive in varying external conditions.