Which nervous system consists of 31 pairs of spinal nerves and 12 pairs of cranial nerves?

The correct answer is the nervous system that includes both cranial and spinal nerves, which is the peripheral nervous system. This system extends beyond the central nervous system (CNS), comprising the brain and spinal cord, to connect the CNS with the limbs and organs. By containing 31 pairs of spinal nerves and 12 pairs of cranial nerves, the peripheral nervous system serves a vital role in transmitting sensory information from the body to the CNS and delivering motor commands from the CNS to the body.

The central nervous system, while integral to overall function, is confined to the brain and spinal cord and does not include the spinal and cranial nerves. The somatic nervous system is a component of the peripheral nervous system that specifically deals with voluntary movements but does not encompass the entirety of the peripheral nervous system. The autonomic nervous system, also a subset of the peripheral system, is responsible for involuntary bodily functions, such as heart rate and digestion, but does not reference the spinal and cranial nerves exclusively. Thus, the peripheral nervous system is the most appropriate selection, as it includes both the spinal and cranial nerves.