Which cranial nerve provides taste sensation to the posterior one-third of the tongue?

The cranial nerve responsible for taste sensation in the posterior one-third of the tongue is cranial nerve IX, also known as the glossopharyngeal nerve. This nerve plays a crucial role in the sensory function of taste in this specific area of the tongue, which is distinct from other cranial nerves that serve different regions or functions.

Cranial nerve VII, the facial nerve, is primarily responsible for taste sensation in the anterior two-thirds of the tongue. Cranial nerve X, or the vagus nerve, does have a minor role in taste, specifically in the area surrounding the epiglottis and the part of the tongue that it innervates. Cranial nerve V, the trigeminal nerve, is mainly involved in the sensation of touch, pain, and temperature of the face and does not have a significant role in taste sensation.

Thus, cranial nerve IX’s specific association with taste in the posterior one-third distinguishes it as the correct answer for this particular question regarding taste sensation in that part of the tongue.