Which cranial nerve has both sensory and motor functions related to the throat?

The glossopharyngeal nerve is indeed the correct answer because it has both sensory and motor functions that pertain to the throat. This cranial nerve is primarily responsible for the sensation of taste from the posterior one-third of the tongue and provides sensory information from the pharynx and tonsils. Additionally, it plays a crucial role in swallowing by innervating the stylopharyngeus muscle, which elevates the pharynx during swallowing.

In contrast, the vagus nerve also has sensory and motor functions associated with the throat, but its scope extends much further into the thoracic and abdominal organs, making it less specific to the throat than the glossopharyngeal nerve. The hypoglossal nerve, on the other hand, is primarily a motor nerve that controls the movements of the tongue and does not provide sensory functions related to the throat. Lastly, the facial nerve is primarily responsible for facial expressions and provides taste sensations from the anterior two-thirds of the tongue, but it does not have significant motor or sensory functions related to the throat itself. Therefore, the glossopharyngeal nerve is the most appropriate choice when considering its specific roles in throat functions.