What is the primary function of the small intestine?

The primary function of the small intestine is to absorb nutrients from the food we consume. After food is broken down in the stomach, it enters the small intestine, where enzymes and bile further digest it. The walls of the small intestine are lined with tiny finger-like projections called villi, which increase the surface area for absorption. These villi facilitate the transport of nutrients, such as carbohydrates, proteins, fats, vitamins, and minerals, into the bloodstream, where they can be delivered to cells throughout the body for energy, growth, and repair.

The other functions listed do not pertain to the small intestine. Storage of waste is primarily carried out by the large intestine, bile is produced in the liver and stored in the gallbladder (not produced by the small intestine), and filtering blood is a function of the kidneys. Therefore, the role of the small intestine as the main site for nutrient absorption is crucial for overall health and metabolism.