Which of the following is an adaptation of the villi that aids absorption?

• A. Rich blood supply
• B. Thin-walled
• C. Large surface area
• D. Lacteal

Answer: (C)

Absorption is made efficient by maximizing the interface between the intestinal contents and the cells that take up nutrients. Villi dramatically boost this interface because they are finger-like projections that increase the surface area available for absorption. On top of each villus, enterocytes have microvilli, forming a brush border that multiplies surface area even further, so more nutrients can cross into the cells at once.

Inside each villus there’s a rich network of capillaries and a lacteal. The capillaries help move water‑soluble nutrients away quickly, while the lacteal handles fats, but the key feature that directly enhances the capacity to absorb across the lining is the large surface area provided by the villi and their microstructures.