Why is the small intestine special for both digestion and absorption?

Correct answer: It receives digestive juices and absorbs through villi

The governing concept is completion of digestion followed by absorption in the small intestine. It receives bile, pancreatic juice and intestinal juice, which help break carbohydrates, proteins and fats into simpler, absorbable substances. Its inner lining contains numerous villi with thin walls and blood capillaries, so digested nutrients can pass efficiently into the circulation. Thus option A is correct; water storage, lung circulation and urine formation are not its primary functions.