Final answer:
A simple, rapid, automatic response to a stimulus is a reflex. The correct answer is C.
Step-by-step explanation:
A simple, rapid, automatic response to a stimulus is known as a reflex. Reflexes are involuntary and are an essential part of an organism's innate behavior, providing an immediate response to a particular stimulus without conscious thought. An example of this is the knee-je rk reflex tested by doctors.
A reflex is an involuntary and nearly instantaneous movement or action in response to a stimulus. It's typically an automatic response that doesn't involve conscious thought, designed to protect the body from potential harm.
For instance, pulling your hand away from a hot surface without consciously deciding to do so is a reflex action. These responses are controlled by the spinal cord and don't require input from the brain. The correct answer is C.