Homeostasis refers to:

• A. The body's energy production
• B. The body's growth and development
• C. The body's immune response
• D. The body's maintenance of a stable internal environment

Answer: (D)

Homeostasis is the body's process of keeping its internal environment stable despite changes outside or inside the body. It involves monitoring and regulating variables like temperature, pH, glucose, and fluid balance, using feedback mechanisms to keep them near a set point. This regulation is a dynamic balance, not a rigid constant, and negative feedback loops are a common way the body maintains it—for example, adjusting heat production or loss to keep body temperature near normal.

The other processes aren’t about maintaining internal stability. Energy production focuses on metabolism and making ATP. Growth and development describe changes in size and function over time. The immune response is about defending the body against pathogens. While all are essential bodily functions, they don’t define homeostasis—the idea is maintaining a stable internal environment.