Which part of the nervous system is enclosed by the skull and vertebral canal?

The correct answer is the Central Nervous System. This part of the nervous system consists of the brain and spinal cord, both of which are protected by the bony structures of the skull and the vertebral column. The Central Nervous System is responsible for processing and integrating information, as well as coordinating reflexes and higher cognitive functions.

In contrast, the Peripheral Nervous System extends beyond the skull and vertebral canal, consisting of nerves and ganglia that connect the Central Nervous System to the rest of the body. The Autonomic Nervous System is a division of the Peripheral Nervous System that regulates involuntary bodily functions, such as heart rate and digestion, and does not reside within the protective structures of the skull and vertebral canal. The Somatic Nervous System, another part of the Peripheral Nervous System, is involved in voluntary movements and sensory information but is also not enclosed by the skull and vertebral canal. Thus, the Central Nervous System uniquely fits the description in the question.