What does homeostasis mean?

• A. The study of living organisms.
• B. The maintenance of stable internal conditions in an organism.
• C. The process of digestion.
• D. The transport of substances within an organism.

Answer: (B)

Keeping the internal environment stable is what homeostasis means. It’s about maintaining a relatively narrow, optimal range for factors like body temperature, pH, and blood glucose, even when external conditions change. The body uses feedback systems to sense when something is off and then acts to bring it back toward the normal range—for example, sweating and expanding blood vessels to cool you down when you’re hot, or shivering to generate heat when you’re cold. Hormonal and kidney regulation help keep blood glucose and fluid balance steady, which is crucial for enzyme function and cell survival. The idea isn’t about keeping every variable exactly the same all the time, but about keeping important conditions within healthy limits. The other options describe related topics (the study of living things, digestion, or transport) but don’t capture the idea of actively maintaining stable internal conditions.