What two main parts make up the Central Nervous System (CNS)?

The Central Nervous System (CNS) is fundamentally composed of two primary components: the brain and the spinal cord. The brain serves as the control center for processing sensory information and coordinating responses, while the spinal cord acts as a pathway for communication between the brain and the rest of the body, facilitating reflexes and information transmission.

By focusing on these two elements, the CNS is distinguished from the Peripheral Nervous System (PNS), which includes all the nerves outside the brain and spinal cord. This distinction is critical in understanding the overall architecture of the nervous system, which is responsible for voluntary and involuntary actions, sensory processing, and homeostasis.

Other components mentioned in the other choices, such as peripheral nerves and cranial or spinal nerves, are integral to the PNS and do not make up the CNS, confirming that the correct answer truly identifies the core constituents of the Central Nervous System.