Question

Where does the absorption of absorbed nutrients occur?

Answer 1

The small intestine is the section of the gastrointestinal tract that lies between the stomach and the large intestine and is responsible for much of the food digesting.

Complete answer:
The absorption of nutrients and minerals from food is the fundamental function of the small intestine. Diffusion is the mechanism through which digested nutrients move into the blood vessels in the intestine's wall. Simple columnar epithelial tissue lines the small intestine's inner wall, or mucosa.
The ingested compounds are delivered to various parts of the body via blood vessels, where they are employed to construct complex substances such as the proteins required by human bodies. The undigested and unabsorbed food is absorbed in the big intestine.
The jejunum is where the majority of nutrients are absorbed, with the following important exceptions:
In the duodenum, iron is absorbed.
The terminal ileum absorbs vitamin B12 and bile salts.
Passive diffusion transports water and lipids along the small intestine.
Active transport, as well as glucose and amino acid co-transport, absorb sodium bicarbonate.
Facilitated diffusion is used to absorb fructose.

Note:
Close to the surface of each villus is a network of capillaries and fine lymphatic vessels known as lacteals. The villi's epithelial cells transfer nutrients (amino acids and carbs) and lacteals from the gut lumen into these capillaries (lipids).