Which system includes the brain and spinal cord?

The correct choice indicates that the central nervous system encompasses both the brain and spinal cord, which are critical components of the overall nervous system. The brain serves as the control center for processing and interpreting sensory information, coordinating movement, and managing cognitive functions such as thought and memory. The spinal cord acts as a conduit for signals between the brain and the rest of the body, facilitating reflexes and transmitting motor commands to muscles.

Understanding the distinction between the central nervous system and other systems is essential. For instance, the peripheral nervous system includes all the nerves outside the brain and spinal cord, connecting the central nervous system to the limbs and organs, while the autonomic nervous system regulates involuntary body functions, such as heartbeat and digestion. The somatic nervous system controls voluntary movements of skeletal muscles. Thus, it is the central nervous system that directly comprises the brain and the spinal cord, making this choice correct.