Maintenance of a constant internal environment is known as what?

• A. Osmosis
• B. Homeostasis
• C. Metabolism
• D. Respiration

Answer: (B)

Maintaining a constant internal environment means keeping conditions like temperature, pH, and nutrient levels in a narrow range despite changes outside. This regulation relies on sensors, a control center, and effectors that act to restore balance when something shifts. A clear example is body temperature: when it rises, the brain signals sweating and expands blood vessels to release heat; when it falls, it can trigger shivering and narrowing of blood vessels to conserve heat. These responses use negative feedback to keep conditions stable, which is essential for enzymes and metabolic processes to function properly.

Osmosis is about water moving across membranes in response to solute differences, not about keeping the whole internal environment steady. Metabolism refers to all chemical reactions in the body, and respiration concerns energy production and gas exchange.