Where do the products of digestion enter the blood?

• A. Stomach
• B. Left subclavian vein
• C. Villi
• D. Liver

Answer: (C)

Absorption of digestion products occurs in the small intestine, where the lining forms finger-like projections called villi that greatly increase surface area. The digested nutrients cross the epithelial cells of the villi and enter the tiny blood capillaries inside each villus. From there, they are carried by the bloodstream (via the hepatic portal vein to the liver for processing) to the rest of the body. This is why the villi are the place where digestion products first enter the blood. The other options don’t fit because the stomach mainly handles digestion, not absorption; the left subclavian vein isn’t involved in nutrient uptake; and the liver receives nutrients after absorption rather than being the entry point for them.