What are reflex actions? Give two examples. Explain a reflex arc

Explanation

Reflex action is a rapid, automatic response to a stimulus which is not under the voluntary control of the brain i.e., it is an involuntary action. It is a simple form of behaviour in which the same stimulus produces the same response every time. e.g.,
(i) If we unknowingly touch a hot plate, we immediately move our hand away from it.
(ii) Moving our foot away on stepping something sharp.
Other examples are knee jerk, Coughing, yawning, sneezing etc.
The pathway taken by nerve impulse in a reflex action is called the reflex arc

Reflex arcs have evolved in animals because the thinking process of brain is not fast enough. However, even after complex neuron networks have come into existence, retlex arc continue to be more efficient for quick responses.