Question

On touching a hot plate, you suddenly withdraw your hand Which category of neurons are first to act and which one is next

Answer 1

On touching a hot plate, first the sensory neurons are activated, which take the
information to the brain or the spinal cord. Next, the motor neurons become active
and bring the impulses from the brain to the muscles. In receiving these impulses, the
muscles contract, and the hand is immediately removed from the hot plate.

Answer 2

The sensory neurons are at first activated that take information  spinal cord/Brain . Information. Then, the motor neurons are activated and bring the brain impulses to the muscles. The muscles get contracted and we remove our hand immediately from the hot plate when these impulses are received.

Explanation:

• If we touch a hot surface inadvertently, we remove our hands without thought immediately. Our hands will burn if we don't do it.
• The heat is detected by the sensory nerves.These nerves are joined to the nerves that move our hand's muscles. This connection is known as arc reflex arc (input) that is, it detects the signal from (input) the nerves  and respond to the instantly (output).
• An arc of reflex allows for automatic and immediate responses. The input nerve & output nerve are linked to it and meets the spinal cord in a bundle. In reality, all the nerves in our body meet the spinal cord in a bundle. The information input thus reaches our brain