A reflex is an automatic response of the body to a stimulus, meaning it happens without us thinking about it. For example, when you touch something hot, your hand quickly pulls away. This quick reaction helps protect you from harm and is controlled by the nervous system, which sends signals to your muscles. Reflexes are important for survival and can be found in many animals, including humans. Common examples include the knee-jerk reflex, where tapping the knee causes it to kick out, and the blinking reflex, which protects the eyes from potential threats. These responses are essential for our everyday safety and functioning.