Answer:
The correct answer is electrical and chemical signals.
Step-by-step explanation:
The nervous system comprises millions of nerve cells, known as neurons. The main function of the neurons is to conduct information from one part of the body to another. The neurons conduct or pass information or messages in the form of electrical signals known as nerve impulses.
In order to generate a nerve impulse, the neurons need to get excited. The stimuli like sound, light, or pressure will excite the nerve cells, however, in the majority of the cases, the chemicals generated by other neurons will stimulate a nerve impulse.