Environmental change that triggers a definite action on the part of the organism serves as a(n) stimulus response effector

In biology, any change that t riggers a definite action from the organism is known as a stimulus. The response is the action that is carried out as a result of the stimulus and the effector is the muscle or muscles that are involved in bringing about the specific response. For example, in the case of touching a hot stove, the heat is the stimulus, the response is the j erking of the hand away from the stove and the effector muscles are those that are in the arm.