What are villi responsible for in the small intestine?

Villi are small, finger-like projections located on the inner surface of the small intestine, and they play a crucial role in the digestive system. Their primary function is to aid in the absorption of nutrients. The vast surface area created by these villi significantly enhances the intestine's ability to absorb nutrients from digested food into the bloodstream.

Each villus is lined with epithelial cells that contain microvilli, which further increase the surface area and facilitate the absorption process. This adaptation allows for efficient uptake of essential vitamins, minerals, and other nutrients, which are critical for the body's overall health and functioning.

The other options describe functions that are not related to the role of villi in the digestive system. Enzymes for digestion are secreted by specialized cells, not created by villi. Waste filtering is a function of organs such as the kidneys, while the transport of oxygen in the bloodstream is performed by red blood cells, not structures in the small intestine. Therefore, the contribution of villi to nutrient absorption is essential within the context of the digestive process.