In which part of the digestive system are digested materials absorbed?

The small intestine is the primary site of nutrient absorption in the digestive system. This elongated, coiled organ follows the stomach and consists of three segments: the duodenum, jejunum, and ileum.

Here, digested food undergoes further breakdown by enzymes released from the pancreas and bile from the liver. The interior walls of the small intestine are lined with villi and microvilli, which significantly increase the surface area available for absorption. These structures ensure that nutrients such as amino acids, simple sugars, fatty acids, and vitamins can efficiently enter the bloodstream.

While the mouth, large intestine, and stomach play roles in digestion, they do not primarily function as sites for absorption. The mouth starts the digestion process through chewing and saliva but doesn't absorb nutrients. The stomach continues digesting food and begins breaking down proteins but absorbs very few substances, mainly alcohol and certain medications. The large intestine primarily focuses on reclaiming water and electrolytes from undigested food and preparing waste for excretion, with minimal nutrient absorption occurring. Thus, the small intestine is specifically designed to facilitate the absorption of nutrients, making it the correct choice.