(N/A) The digestion of food in humans occurs in the following stages:
$1$. Carbohydrates: Digestion begins in the mouth where salivary amylase breaks down starch into simpler sugars. It continues in the small intestine,where pancreatic amylase converts remaining carbohydrates into glucose.
$2$. Proteins: Digestion begins in the stomach with the action of pepsin in an acidic medium. It is completed in the small intestine by pancreatic enzymes like trypsin and chymotrypsin,which break proteins down into amino acids.
$3$. Fats: Digestion occurs primarily in the small intestine. Bile salts emulsify large fat globules into smaller droplets,and then the enzyme lipase breaks them down into fatty acids and glycerol.