Which two main parts constitute the nervous system?

The nervous system is primarily composed of two main parts: the central nervous system (CNS) and the peripheral nervous system (PNS). The central nervous system includes the brain and spinal cord, which serve as the control center for processing information and coordinating responses. The peripheral nervous system comprises all the nerves that branch out from the central nervous system to connect to the rest of the body, including limbs and organs. This division is crucial for understanding how different components of the nervous system function and interact.

The other options represent subcategories or specific functions within the broader nervous system framework. For example, the sympathetic and parasympathetic nervous systems are divisions of the autonomic nervous system, which is itself part of the peripheral nervous system. Likewise, the somatic and autonomic systems refer to another classification of functions related to voluntary and involuntary control of body activities. Lastly, the terms cerebral and spinal nervous system are not standard divisions of the nervous system, as they do not encompass the entirety of how the nervous system is structured and functionally organized.