Final answer:
The hypoglossal nerve is the twelfth cranial nerve responsible for controlling the muscles of the tongue.
Step-by-step explanation:
The hypoglossal nerve is the twelfth cranial nerve that is responsible for contraction of the muscles of the tongue, except for the palatoglossus muscle.
It is a motor nerve and plays a crucial role in speech, swallowing, and tongue movement. The hypoglossal nerve is tested by assessing the movement of the tongue, such as sticking it out straight, to check for any impairments.