1. The circular muscles of the mouth enable the food to be pushed in to the oral cavity and to be moved around. 2. The surface muscles of the jaw help in biting and chewing actions and move the jaw up and down, forward and backward during mastication.3. The teeth help in cutting and grinding while tongue movements evenly spread out the food and help in mixing it with saliva. 4. Hence , we can say that mouth is a munching machine.