What term describes the body's reaction to a stimulus?

• A. Stimulus
• B. Hormone
• C. Response
• D. Digestion

Answer: (C)

Response describes the body's reaction to a stimulus. A stimulus is anything that triggers a change—for example heat, light, touch, or a chemical signal. The response is the body's action or physiological change that follows, such as pulling your hand away from a hot surface or increasing heart rate. Hormones can mediate responses, but they’re signaling molecules within certain responses, not the general idea of reacting to a trigger. Digestion, on the other hand, is a process of breaking down food, not the reaction to a stimulus. So the best way to describe the body's reaction to something that prompts a change is the response.