What is the role of saliva in the digestion of food?
Saliva plays an important role in the digestion of food. It is a fluid secreted by the salivary glands in our mouth.
Firstly, saliva wets the food to make its passage smooth through the digestive tract, as the lining of the canal is soft. This helps the food move easily along the alimentary canal.
Secondly, saliva contains an enzyme called salivary amylase. This enzyme breaks down starch, which is a complex molecule, into simple sugar. The food is mixed thoroughly with saliva while chewing by the muscular tongue, allowing the enzyme to act on the starch effectively.
Explanation
The textbook context clearly mentions two key roles of saliva: (1) wetting the food to make its passage smooth through the soft-lined digestive tract, and (2) containing salivary amylase enzyme that breaks down complex starch into simple sugar. These two points cover the complete role of saliva in digestion as per NCERT Class 10 Science textbook.