What is the action primarily controlled by the Vagus nerve?

The Vagus nerve is primarily responsible for regulating visceral sensations and motor functions, making it a crucial component of the autonomic nervous system. It innervates structures in the neck, thorax, and abdomen, influencing functions such as heart rate, gastrointestinal peristalsis, and respiratory rate. Specifically, the Vagus nerve carries sensory information from internal organs and provides motor innervation to muscles involved in swallowing and vocal cord movement. This diverse range of functions aligns it with visceral control rather than more localized actions associated with other cranial nerves.

The other options pertain to functions controlled by different cranial nerves: motor control to the tongue is primarily governed by the Hypoglossal nerve, neck muscles are mainly served by the Accessory nerve, and eye movement is predominantly managed by the Oculomotor, Trochlear, and Abducens nerves. This differentiation underscores why the Vagus nerve's role in visceral sensations and motor functions is the correct answer.