Define homeostasis and give an example of a physiological feedback mechanism in humans.

• A. Homeostasis is the maintenance of a stable internal state; negative feedback, such as temperature regulation via sweating or shivering, returns the system to set points.
• B. Homeostasis is the process of division of cells in a tissue.
• C. Homeostasis refers to the genetic variation in a population.
• D. Homeostasis is the energy produced by mitochondria.

Answer: (A)

Homeostasis is the maintenance of a stable internal environment to keep cells functioning properly despite changes outside or inside the body. A physiological feedback mechanism in humans is a negative feedback loop that keeps body temperature near a set point. If internal temperature rises, sensors trigger cooling responses like sweating and vasodilation to lose heat; if it falls, warming responses such as shivering and vasoconstriction generate or conserve heat. These actions oppose the initial change and bring temperature back toward the normal range, illustrating how a small deviation is corrected to restore balance. The set point is the target value the body aims to maintain, around 37°C for core temperature in humans. This is negative feedback because the response counters the deviation rather than amplifying it. Other descriptions—cell division, genetic variation, or mitochondrial energy production—don’t describe maintaining stable internal conditions or using a corrective feedback loop.