How is small intestine designed to

solution:
Small intestine is lined by epithelium which is specialised to absorb. It has mechanism to increase its absorbing surface area several times.

(i) Villi are transverse folds of intestine wall that not only increase surface area but also reach deep into the lumen of intestine for absorption of digested food. Villi possess blood capillaries and lacteals (lymph vessels) for quick transport of absorbed food.

(ii) Microvilli are the columnar cells of the intestinal epithelium have fine microscopic outgrowths called microvilli. Microvilli increase the surface area of epithelial cells.