Define homeostasis.

Homeostasis refers to the maintenance of a stable internal environment within an organism despite fluctuations in the external environment. This concept is crucial for the survival of living organisms, as it ensures that conditions such as temperature, pH, and electrolyte balance remain within a narrow range that is optimal for physiological processes. For example, humans regulate their body temperature through mechanisms like sweating or shivering, depending on external conditions.

This balance allows systems to function properly despite changes that may occur in their surroundings. The other choices provided involve different biological processes: cellular repair and regeneration pertains to how cells heal and replace damaged tissues, the ability to adapt to a wide range of environments describes a broader ecological or evolutionary concept rather than internal regulation, and cell division and growth are processes related to development and reproduction. Hence, the correct definition of homeostasis centers specifically around the stability of an internal environment in the face of external changes.