Help to summarize various compounds (starch, protein, lipids, vitamins, etc. ) mainly absorption.

Starch is digested in the mouth and small intestine because there is salivary amylase in the mouth and intestinal juice and pancreatic juice in the small intestine. The main absorption site is the small intestine, because there are many small intestinal villi in the small intestine!

Protein is digested by pepsin in the stomach. The main absorption site is the small intestine, and the same is true!

Lipids can only be decomposed and digested in the small intestine and are influenced by bile. Or the small intestine.

Vitamins are absorbed directly.

It can be concluded from the above that the small intestine is the main absorption place! Because there are many small intestinal villi to help absorption, the absorption area is greatly increased. It's also a place to digest! Because the small intestine has two kinds of digestive juices, pancreatic juice and intestinal juice, which can digest the above substances!