How is the small intestine designed to absorb digested food?

Correct option: All of the above

For absorption of digested food, small intestine is the most important part of the alimentary canal. This is because of the following reasons:
- The mucosa of the small intestine is lined with a simple columnar epithelium in which absorbent cells are embedded that help absorb nutrients from food in the small intestine.
- The small intestine's villi are small, finger-like protrusions that generally extend into the lumen of the small intestine. The size of each villus is about 0.5-1.6 mm in length. These finger-like protrusions help increase the surface area for absorption.
- Villi are composed of a network of capillaries to absorb digested simpler food molecules and lymph vessels specifically to help in absorption of fatty acids.

Hence the correct answer is option D.