Which system includes the brain and spinal cord?

The central nervous system (CNS) is the part of the nervous system that includes the brain and spinal cord. This system is responsible for processing and transmitting information throughout the body, serving as the main control center. The brain processes sensory information, controls thoughts, and coordinates voluntary movements, while the spinal cord acts as a bridge for signals between the brain and the rest of the body, facilitating reflex actions and transmitting information to and from the peripheral nervous system.

The other systems mentioned do not include both the brain and spinal cord. The peripheral nervous system connects the central nervous system to limbs and organs but consists of all the nerves outside the CNS. The autonomic nervous system regulates involuntary bodily functions like heartbeat and digestion but is a subset of the peripheral nervous system. The somatic nervous system is also part of the peripheral nervous system, focusing on voluntary movements and the relay of sensory information to the CNS. Therefore, the central nervous system is accurately identified as the system that encompasses both the brain and spinal cord.