Which cranial nerve controls taste on the posterior one-third of the tongue?

The cranial nerve that controls taste sensation from the posterior one-third of the tongue is cranial nerve IX, also known as the glossopharyngeal nerve. This nerve is responsible for various functions, including conveying taste sensations from this specific area of the tongue. The importance of cranial nerve IX extends beyond taste, as it also aids in swallowing and provides sensory input from the oropharynx and the auditory canal.

Cranial nerve VII, the facial nerve, is primarily responsible for taste in the anterior two-thirds of the tongue, while cranial nerve X, known as the vagus nerve, plays a role in taste for regions such as the epiglottis and the pharynx but does not cover the posterior one-third of the tongue. Cranial nerve VIII, the vestibulocochlear nerve, is mainly involved in hearing and balance, not taste sensation. Therefore, the specific role of cranial nerve IX in taste perception from the posterior one-third clearly establishes it as the correct answer.