Final answer:
The facial nerve or CN VII is responsible for facial movements, taste sensation in the anterior two-thirds of the tongue, salivation, and some aspects of hearing and equilibrium.
Step-by-step explanation:
The cranial nerve that is primarily responsible for facial movements and expressions, including taste sensation in the anterior two-thirds of the tongue, controlling tears and salivation, and some aspects of hearing and equilibrium, is the facial nerve or CN VII. It is one of the nerves that contain both sensory and motor fibers. The facial nerve (CN VII) is also involved with preganglionic parasympathetic fibers related to the lacrimal and salivary glands. In addition to facial expressions, the facial nerve is responsible for taste sensation, as it carries the sensory information from the majority of the tongue, and it plays a role in the salivation process in the anterior oral cavity. The gag reflex, however, is controlled mainly by the glossopharyngeal nerve (CN IX).
The arrow that points to the facial nerve (CN VII) on a diagram will indicate a nerve running through the internal acoustic meatus into the facial canal and finally exiting at the stylomastoid foramen. Unlike the purely sensory optic nerve (CN II), the facial nerve has a mixed function, providing sensory, motor, and parasympathetic innervation.
In summary, the facial nerve is crucial for various functionalities related to the face, including movement, sense of taste, and autonomic properties.