Final answer:
Salivary amylase is an enzyme in saliva that specifically breaks down carbohydrates in the mouth, starting the digestion process by hydrolyzing starch into smaller sugar molecules.
Step-by-step explanation:
Salivary amylase is a digestive enzyme found in saliva, which is secreted by the salivary glands. Its main function is the decomposition of carbohydrates by acting on starch. Specifically, salivary amylase hydrolyzes the bonds within starch molecules to begin the process of digestion in the mouth, producing smaller carbohydrate molecules like maltose and dextrins.
Therefore, the correct answer to the question about what salivary amylase digests is b. carbohydrates. It does not break down proteins, fats, or vitamins. These macromolecules are digested by other enzymes such as trypsin (proteins) and lipase (fats) secreted at different stages of the digestive system.