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Answer brief : (i) Why are villi prese...

Answer brief :
(i) Why are villi present in the intestine and not in stomach?
(ii) How does pepsinogen change into its active form?
(iii) What are the basic layers of the wall of alimentary canal?
(iv) How does bile help in digestion of fat?

Text Solution

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(i) Villi increase the surface area of digestion and absorption of food.
(ii) HCl of oxyntic cells of gastric glands activates pepsinogen to pepsin.
(iii) Mucosa, submucosa, muscular coat and peritoneum.
(iv) Bile provides alkaline medium for the proper activity of pancreatic and intestinal enzymes and emulsifies the fats to increase their surface area for the action of lipases.
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