Final answer:
The levator anguli oris is a facial muscle that helps elevate the angle of the mouth, aiding in facial expressions like smiling and important digestive functions such as chewing and swallowing.
Step-by-step explanation:
The levator anguli oris is a facial muscle that elevates the angle of the mouth. This muscle plays a critical role in facial expression, particularly in the expression of joy or happiness as it contributes to the action of smiling. Working alongside other facial muscles, such as the buccinator muscle which compresses the cheek, the orbicularis oris which moves the lips, and various muscles that help in the mastication process, the levator anguli oris aids in the important digestive functions of positioning food for optimal chewing, gathering food into a bolus, and aiding in the swallowing process. The dynamic interplay of these muscles also facilitates other functions such as speaking and maintaining the contents of the mouth.