Texas A&M University (TAMU) BIOL112 Introductory Biology II Exam 3 Practice

The small intestine plays a critical role in the digestive process, primarily serving as the main site for nutrient absorption. After food is broken down in the stomach and enters the small intestine, the digestive system continues to break down nutrients into smaller components. The walls of the small intestine are lined with villi and microvilli, which greatly increase the surface area available for absorption. This structural adaptation allows for the efficient uptake of amino acids, fatty acids, monosaccharides, vitamins, and minerals into the bloodstream.

While the other options describe various functions related to digestion, they do not capture the primary role of the small intestine. For instance, storing food is primarily a function of the stomach. Mechanical digestion, which involves physically breaking down food, occurs in various parts of the digestive system, including the mouth and stomach, but not primarily in the small intestine. The production of digestive enzymes does take place in the small intestine, but it is not the primary role; rather, the focus is on the absorption of the nutrients extracted from digested food.