What part of the nervous system primarily comprises the brain and spinal cord?

The central nervous system is the primary component that includes both the brain and the spinal cord. This system is responsible for processing information and coordinating activity throughout the body. It serves as the main hub for receiving sensory input, processing that information, and then sending out responses. Given that the brain is the center for cognitive functions and the spinal cord is critical for transmitting signals between the brain and the rest of the body, this choice accurately represents the best answer to the question about which part of the nervous system encompasses these key structures.

The peripheral nervous system, on the other hand, consists primarily of the nerves that branch out from the spinal cord and extend to other parts of the body, while the autonomic and somatic nervous systems are subdivisions of the peripheral nervous system. The autonomic nervous system regulates involuntary functions, such as heart rate and digestion, while the somatic nervous system controls voluntary movements. Therefore, while these systems are essential to overall nervous system function, they do not include the brain and spinal cord, which is why the central nervous system is the correct choice.