Who defined stress as, 'the response of the body to any demand, whether it is caused by, or results in, pleasant or unpleasant conditions'?

Dr Hans Selye

Explanation:

The concept of stress was introduced by Dr Hans Selye, who was a Hungarian endocrinologist. He is often referred to as the 'Father of Stress' due to his work in understanding, and giving a scientific explanation to, stress.

He wrote about GAS (General Adaptation Syndrome), or the stress syndrome, describing how the body reacts to stress in three stages of coping. These are as follows:

it provides an alternative energy pathway for the reaction to proceed.

a catalyst is a substance that speeds up the rate of a chemical reaction but is not consumed during the course of the reaction.

catalysts increase the rate of reaction without being used up. they do this by lowering the activation energy needed. with a catalyst, more collisions result in a reaction, so the rate of reaction increases. different reactions need different catalysts.

a catalyst works by providing an alternative reaction pathway to the reaction product. the rate of the reaction is increased as this alternative route has a lower activation energy than the reaction route not mediated by the catalyst.