Final answer:
The action of the masseter muscle is primarily involved in chewing, where it elevates the lower jaw to crush and grind food. This muscle plays a crucial role in the mastication process.
Step-by-step explanation:
The action of the masseter muscle is involved in the process of chewing. The masseter is one of the muscles of mastication and it plays a critical role in elevating the jaw to allow the teeth to come together and grind food. This muscle is located in the jaw and is one of the strongest in the human body. Its primary function is not involved with swallowing, moving the lips, or closing the eye.
When you chew food, the masseter contracts, which raises the lower jaw to meet the upper jaw. This action crushes and grinds the food, making it easier to swallow. So, in response to the original question, the correct answer is (b) chewing.