Gonna need a bit more information then that if you want an answer.
Answer:
I think the answer is C I hope you get this right, tell me if I am wrong plz
Explanation:
The right option is; They allow the body to react to stimuli.
Nerve cells, (also called neurons) are specialized cells that are found in their millions in the nervous system. Nerve cells are created to stimulate other cells in the body. They transmit messages in the form of electrical signals within the body, and they allow the body to respond to stimuli. Neurons are grouped into three types which are; sensory neurons, motor neurons and association neurons.
These substances are called reactants.
