Which two systems comprise the nervous system?

The nervous system is subdivided into two primary components: the central nervous system (CNS) and the peripheral nervous system (PNS). The CNS includes the brain and spinal cord, serving as the core processing center for information and coordination of bodily functions. It interprets sensory information and initiates responses. On the other hand, the PNS consists of all the nerves that branch out from the CNS to the rest of the body, linking the brain and spinal cord to limbs and organs and allowing for communication between the body and the CNS. This division is fundamental for understanding how signals are transmitted throughout the body, making option A the correct choice.

Other choices mentioned refer to different classifications within or related to parts of the nervous system. The somatic and autonomic systems are subdivisions of the PNS that manage voluntary and involuntary control, respectively. The sensory and motor classifications refer to the functional branches, with sensory nerves conveying information to the CNS and motor nerves carrying commands from the CNS to the muscles. The endocrine and exocrine systems are completely separate systems involved in hormone production and secretion rather than neural signaling, so they do not pertain to the structure of the nervous system.