Villi maximize absorption in the small intestine

Steps:

• Recall that the ileum is the final section of the small intestine where most nutrient absorption occurs.
• Identify villi as finger-like projections lining the intestinal wall.
• Determine their structural role: they contain microvilli, blood vessels, and lacteals to facilitate nutrient uptake.
• Eliminate options unrelated to absorption, confirming the primary function.

Why A is correct:

• Villi increase the surface area by up to 600 times, per the definition of intestinal adaptations for efficient diffusion and active transport of nutrients.

Why the others are wrong:

• B: Peristalsis is performed by smooth muscle layers, not villi.
• C: Mucus is secreted by goblet cells in the epithelium, not villi.
• D: Amylase is produced by salivary glands and pancreas, not intestinal villi.

Final answer: A