What are the three basic stages of Selye's biological adaptation?

• A. Alarm, Resistance, Exhaustion
• B. Alarm, Recovery, Exhaustion
• C. Stimulus, Resistance, Fatigue
• D. Preparation, Activation, Depletion

Answer: (A)

Selye’s general adaptation syndrome describes how the body responds to stress in a predictable sequence. The three stages are Alarm, Resistance, and Exhaustion. In Alarm, the body detects the stressor and mounts a rapid response (fight-or-flight), releasing adrenaline and preparing energy. During Resistance, the body tries to cope with the ongoing stress, sustaining physiological activity and using resources to adapt. If the stress continues, resources become depleted and the body enters Exhaustion, where defenses weaken and the risk of illness or dysfunction increases. This is why Alarm, Resistance, Exhaustion is the best fit—the terms match the well-established progression of the GAS. The other options use nonstandard stages or mix in terms like Recovery or Fatigue that don’t form the official sequence.