The small intestine has three parts and those include:
Duodenum: The duodenum is the first part of the small intestine. The main purpose of that is to complete the first phase of digestion. The duodenum has some kind of enzymes where it can break down food.
Jejunum: the jejunum is the second part of the small intestine. After the food is done being broken down by the duodenum, it moves into the jejunum where the walls absorb the food's nutrients that the body needs.
lluem: the lluem is the third and final part of the small intestine. it absorbs the bile acids and vitamin B12 which of course the body needs.
Hope this helped :)
Have a great day
