Definition: This is the actions of organisms in response to stimuli.

The definition this is the action of organisms in response to stimuli is known as homeostasis.

Explanation:

The process by which organisms react to stimuli that keep the conditions in their body suitable for life is called homeostasis. They are the organisms that maintain the stable internal environment. Stimulus is the environmental change that directly influences the activity of a living organism.

A stimulus is a change in the physical or chemical structure of an organism's internal or external environment. The ability to respond to external stimuli is called sensitivity. The plant bend towards the sun is an example of response to a stimuli in an organism.

The actions of organisms in response to stimuli is called the behavior.

Explanation:

The actions of an organism in response to a stimulus are called as its behavior.

In a reaction chain of reacting to an environmental reaction begins initially with a stimulus. External stimulus triggers the sensory receptors which passes the information to the nervous system.

The control system of the body, the brain processes the information and decides the response. The response signal is then transferred to the effector, which expresses the behavior.

The smell of food triggers a dog's nose and passes the information to brain, which sends information to the mouth to secrete saliva and drool.