If the inner surface of the ileum in the human small intestine was smooth, rather than being folded and subdivided into villi, which of the following statements would be true?
A. The rate of absorption of digested food molecules would be higher. Because the digested food would pass more easily through the digestive tract.
B. Digestion would not be as effective, because there would be fewer cells secreting trypsin (a protein-digesting enzyme).
C. Humans would have needed to evolve a much longer small intestine to absorb sufficient nutrients from their food.
D. Humans would not be able to survive, because the digestive tract would be more susceptible to damage.

Question

If the inner surface of the ileum in the human small intestine was smooth, rather than being folded and subdivided into villi, which of the following statements would be true?
A. The rate of absorption of digested food molecules would be higher. Because the digested food would pass more easily through the digestive tract.
B. Digestion would not be as effective, because there would be fewer cells secreting trypsin (a protein-digesting enzyme).
C. Humans would have needed to evolve a much longer small intestine to absorb sufficient nutrients from their food.
D. Humans would not be able to survive, because the digestive tract would be more susceptible to damage.

Vedantu Content Team · Accepted Answer

Hint: The inner surface in the ileum of the small intestine is said to have many folds which are known as villi, these are finger-like projections which help in increasing the surface area for absorption of minerals in the intestine.Complete answer: In our small intestine, there are foldings in the mucosa which helps to increase the surface area for the absorption of the digested food. Further located on the epithelial surface of the small intestine are there millions of small villi also called the Intestinal epithelial cell on each villus and it is characterized by a brush border which further increases the surface area. Thus, for the compensation of this and to have an effective absorption of nutrients, our intestine would need to be much-much longer which can't be imagined. Additional information: The ileum functions to further digest food coming from the stomach and other regions of the small intestine. It absorbs nutrients (vitamins, minerals, carbohydrates, fats, proteins) and water from food substances so that they can be used by the body. The small intestine connects the colon and the stomach.Hence the correct option is (C), humans would have needed to evolve a much longer small intestine to absorb sufficient nutrients from their food.Note:  These intensive folding in the intestinal ileum region along with the presence of villi are the reason why humans can absorb more amounts of food.