Which statement best defines homeostasis and negative feedback?

• A. Negative feedback increases deviations from the set point.
• B. Homeostasis involves maintaining a stable internal environment.
• C. A positive feedback loop amplifies changes to reach a new set point.
• D. Homeostasis is maintaining a stable internal environment; negative feedback reduces deviations (e.g., body temperature regulation via sweating and shivering)

Answer: (D)

Maintaining a stable internal environment is what this question is asking about. Homeostasis refers to keeping variables like temperature, pH, and glucose within narrow limits despite changes outside the body. Negative feedback is the mechanism that detects a deviation from the desired set point and triggers responses that oppose that change, pulling the variable back toward that set point.

For temperature regulation, sensors detect when the body gets too hot or too cold, the control center compares what’s happening to the set point, and effectors such as sweat glands or muscles produce cooling or heating actions to restore normal temperature. So, homeostasis is about stability, and negative feedback reduces deviations to maintain that stability.

Other statements would either imply that negative feedback makes deviations larger or describe a process that pushes toward a new state, which isn’t how most homeostatic systems work.