The diagram shows a reflex arc. Study it and answer the following questions.

1. Name the parts numbered a to d.
2. Using the letters of alphabet shown in the diagram, indicate the direction in which the impulse enters and leaves part c. X to Y or Y to X?
3. What is reflex action?
4. With the help of a flow chart, show a simple reflex action.

1. The parts numbered a to d are:
   a → sensory neurons
   b → motor neurons
   c → association neurons
   d → cell body of motor neurons
2. The impulse enters through X and leaves through Y.
3. An automatic, spontaneous and mechanical response to a stimulus; controlled by the spinal cord without the involvement of the brain is called a reflex action.
4. Below flow chart shows a simple reflex action of immediate withdrawal of hand on touching a hot object: