Question

A digestive enzyme, salivary amylase, in the salvia being digestion of
A. Protein
B. Nucleic acids
C. Fats
D. Carbohydrates

Answer 1

Hint:The salivary glands secrete a viscous fluid called salvia. It contains water, salts, mucin and enzyme salivary amylase.

Complete answer:
A. Proteins: proteins are digested by proteolytic enzyme pepsin which hydrolyses proteins into peptides ( proteoses and peptones) Peptic or chief cells secrete pepsinogen which is inactive form. It is activated by HQ and active form is pepsin.
Pepsinogen $\xrightarrow{{HQ}}$ Pepsin
(Inactive form) (Active form)
B. Nucleic acid: Nucleic acids are digested in the small intestine by nucleases, nucleotidases and nucleosidases which are secreted by pancreas and intestinal juices.
C. Fats: Bile juice secreted by liver, helps in the emulsification of fats it breaks large fat globules into small globules.
D. Carbohydrates: Saliva contains salivary amylase. The saliva secreted into the buccal cavity contains electrolytes (Na$^+$, K$^+$, Cl$^-$, HCO$_3$$^-$) and enzymes, salivary amylase and lysozymes. The chemical process of digestion is initiated in oral cavity by hydrolytic action of carbohydrate splitting enzyme, the salivary amylase. About 30% of starch is hydrolysed by this enzyme into a disaccharides-maltose.
Starch $\dfrac{\text{Salivary Amylase}}{pH \; 6.8}\to$ Maltose

Hence the correct answer is option (D) Carbohydrates.

Note:Salvia is mainly produced by three paves of salivary glands, the parotids (check), the submaxillary/submandibular (lower jaw) and the sublinguals (below the tongue). These glands are situated just outside the buccal cavity.