The central nervous system comprises

• A. Brain and spinal cord
• B. Peripheral nerves
• C. Cranial nerves
• D. Autonomic nerves

Answer: (A)

The central nervous system is the brain and spinal cord—the body's main command and processing center. The brain interprets sensory information, stores memories, and coordinates complex actions, while the spinal cord serves as the main conduit between the brain and the rest of the body and also handles many reflexes. The other options are outside the CNS: peripheral nerves carry information to and from the CNS, cranial nerves connect the brain to structures in the head and neck, and autonomic nerves regulate involuntary functions in the viscera. Thus, the brain and spinal cord constitute the CNS.