Explain the role of the mouth in the digestion of food.

(N/A) The teeth crush food into small pieces,increasing the surface area for enzyme action.
$(b)$ Saliva is secreted by the salivary glands,which moistens the food and contains the enzyme salivary amylase.
$(c)$ Salivary amylase breaks down complex starch into simpler sugars (maltose).
$(d)$ The tongue helps in the thorough mixing of food with saliva and facilitates swallowing by forming a food bolus.