AP BIOLOGY

Detailed explanation-1: -These are found in the small intestine’s inner walls. Functions: Villi enhance the absorption surface area.

Detailed explanation-2: -Villi are present in the small intestine to increase the surface area of absorption. The stomach, on the other hand, is an organ that primarily stores food temporarily, along with helping in digesting proteins. Hence, the presence of villi is more justified in the small intestine and not in the stomach.

Detailed explanation-3: -The duodenum and jejunum contain villi, which are covered with absorbent cells (enterocytes with microvillous, brush border) as well as a very small number of goblet cells, with crypts of Lieberkühn between the villi.

Detailed explanation-4: -Villi are tiny, finger-like projections from the wall of the small intestine. They line the inner surface of the small intestine. Their role is to increase the surface area within the small intestine. This will lead to the increase of the surface area of absorption as it is the main function of the small intestine.

Detailed explanation-5: -Your villi alternate with depressions called crypts, where your small intestine manufactures the cells that form the villi and other parts of the intestinal lining.