What comprises the Peripheral Nervous System (PNS)?

The Peripheral Nervous System (PNS) consists of all the nerves and ganglia that exist outside of the central nervous system (CNS), which includes the brain and spinal cord. The PNS is responsible for transmitting messages between the CNS and the rest of the body, facilitating communication with muscles, organs, and sensory receptors. This division plays a crucial role in both voluntary movements (such as walking) and involuntary actions (such as reflexes).

The other options represent components of the nervous system, but not the PNS specifically. The brain and spinal cord constitute the CNS, while somatic and cranial nerves are subsets of the PNS, and the cerebellum and cerebrum are specific parts of the brain, also within the CNS. Therefore, the definition of the PNS accurately points to the nerves and ganglia that operate outside the central structure, making it the correct choice.