What is primarily responsible for processing external stimuli?

The correct answer highlights the role of the Central Nervous System (CNS) in processing external stimuli. The CNS, which includes the brain and spinal cord, is integral to receiving sensory information from the body and the environment, and it is responsible for interpreting and responding to these stimuli. Sensory neurons collect data from the surroundings and transmit it to the CNS, where complex processing occurs, leading to perceptions and actions.

The other options refer to specific aspects or divisions of the nervous system. The Autonomic Nervous System primarily manages involuntary functions such as heart rate and digestion and is not primarily involved in processing external stimuli. The Peripheral Nervous System encompasses all the nerves outside the CNS, serving as a communication system between the CNS and the body, but it is not the main center for processing information. The Somatic Nervous System is a component of the Peripheral Nervous System responsible for voluntary movements and sensory information but does not itself process data; that responsibility lies within the CNS. Thus, the Central Nervous System is correct as it is the central hub for processing and interpreting external stimuli.