If the ventral root of a reflex arc controlling leg movement is severed, what part of the nerve pathway will block the nerve impulse?

motor neuron
sensory neuron
interneuron
receptor

Motor neuron.

Explanation:

Motor neuron is a nerve impulse that transfer the messages from the central nervous system to the effector organ. The effector organ can be any muscles, gland or tissue.

The ventral root of reflex arc that controls the leg movement is severed, motor neuron pathway blocks the nerve impulse because the information cannot be  transferred from the CNS to the leg.

Thus, the correct answer is option (1).

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