What makes up the central nervous system?

• A. The brain and spinal cord.
• B. The brain and peripheral nerves.
• C. The spinal cord only.
• D. The nerves outside the skull.

Answer: (A)

Think of the central nervous system as the body's command center, comprising the brain and spinal cord. The brain handles processing, perception, memory, and decision-making, acting as the main control hub. The spinal cord serves as the main conduit, transmitting information between the brain and the rest of the body and can coordinate simple reflexes on its own. The other options point to components that belong to the peripheral nervous system, which includes nerves outside the brain and spinal cord that carry information to and from the CNS. Leaving out the brain would omit essential processing, while focusing only on the spinal cord would miss the brain’s crucial role. So, the central nervous system is the brain together with the spinal cord.