Answer – Hans Seyle
János Hugo Bruno "Hans" Selye, was an Endocrinologist who postulated, based on physiological and psychobiological analysis, that when an event threatens an organism's well-being (a stressor), it leads to a three-stage bodily response:
Stage 1: Alarm.
Stage 2: Resistance.
Stage 3: Exhaustion.
This model was what he called General Adaptation Syndrome (GAS).
