4. The muscle responsible for the depression of the mandible (opening of the mouth)is a. Masseter Temporalis c. Medial plerygold will . Buccinator e. Lateral pterygold

The correct answer is b. Temporalis.<br /><br />The temporalis muscle is responsible for the depression of the mandible, which means it helps in opening the mouth. The masseter muscle, on the other hand, is primarily responsible for elevating the mandible, or closing the mouth. The medial pterygoid, buccinator, and lateral pterygoid muscles also play roles in jaw movement, but the primary muscle responsible for opening the mouth is the temporalis.