Digestion in $Hydra$ is:

Which one of the following enzymes initiates protein digestion?

What name would you suggest for food that is thoroughly mixed with gastric juices by the churning movements of the muscular stomach wall?

Given below are two statements:
$Statement-I$: Chymotrypsin converts proteins as well as proteoses and peptones to polypeptides.
$Statement-II$: Trypsin converts polypeptides to dipeptides.
In the light of above statements, choose the most appropriate answer from the options given below.

Protein digesting enzyme pepsin shows highest activity at an optimum pH . . . . . . .

In human beings,digestion of carbohydrates starts from the mouth. How much percentage of it is digested in the mouth?