Final answer:
The abducens nerve is cranial nerve VI (6) and is responsible for the motor function of eye movement, particularly the abduction of the eyes.
Step-by-step explanation:
The abducens nerve is known as the cranial nerve VI (6). This nerve is responsible for the contraction of the lateral rectus muscle of the eye, which is one of the six extraocular muscles that control eye movement. The abducens nerve, therefore, plays a crucial role in motor function for eye movement. It is specifically involved in allowing the eyes to move outward, away from the midline of the body, which is known as abduction. This is distinct from the other cranial nerves like the optic (CN II) nerve, which is purely sensory and involved in vision, or the vestibulocochlear (CN VIII) nerve, which is involved in hearing and balance.