(i) Herbivores like cows eat grass, which is rich in cellulose and difficult to digest, so they have a longer small intestine to allow complete digestion. Carnivores like tigers eat meat, which is easier to digest, so they have a shorter small intestine. Thus, the length of the small intestine is related to the type of food consumed.
(ii) The pancreas secretes pancreatic juice which contains enzymes that digest carbohydrates, proteins, and fats. Bile juice, produced by the liver and stored in the gall bladder, is released into the small intestine. It does not contain enzymes but helps in the emulsification of fats — breaking large fat globules into smaller ones — which makes it easier for enzymes to act on them. Bile also makes the medium alkaline, which is necessary for enzyme action.
(iii) The inner lining of the small intestine has finger-like projections called villi, which greatly increase the surface area for absorption. Villi have a rich network of blood vessels that absorb the digested food into the blood.
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