Final answer:
The correct option is B). Most nutrient absorption occurs in the duodenum and jejunum of the small intestine. The jejunum is mainly where carbohydrates, amino acids, fatty acids, and vitamins are absorbed, while the duodenum absorbs iron and fatty acids. The ileum also plays a role in absorbing certain nutrients like vitamin B12 and bile salts.
Step-by-step explanation:
Most nutrient absorption occurs in the duodenum and jejunum(b), which are parts of the small intestine. The duodenum, being the first part of the small intestine right after the stomach, is where iron is absorbed and where some chemical digestion takes place, such as the absorption of fatty acids. The duodenum receives digestive juices that break down food particles into glucose, triglycerides, and amino acids.
The jejunum, which is the second part of the small intestine, is responsible for the bulk of chemical digestion and nutrient absorption. Here, carbohydrates, amino acids, fatty acids, and many vitamins are absorbed into the bloodstream through the intestinal lining. The structure of the small intestine, with its circular folds, villi, and microvilli, greatly increases the surface area for absorption, making the jejunum exceptionally efficient at this process.
The ileum is the third and final part of the small intestine where certain nutrients, such as vitamin B12 and bile salts, are absorbed. While some nutrient absorption also takes place in the stomach and large intestine, about 95 percent of nutrients are absorbed in the small intestine, primarily in the jejunum.