Question

Case: Neena was writing a project report on modes of nutrition in different organisms. Heterotrophic organisms display three modes of nutrition i.e., saprophytic, parasitic and holozoic. In the holozoic mode of nutrition, a study on the digestive system of different animals showed that the length of the food pipe or oesophagus in different animals are different. The study showed that herbivores have a longer small intestine as compared to carnivores.
Help Neena to complete her report by answering the following question:

State the adaptations of the small intestine that help in the absorption of food.

• A. Greater length and less width causes slow movement of food
• B. Presence of a larger number of villi
• C. Single-cell epithelium
• D. All of the above.

Answer 1

The correct option is D All of the above.

Small intestine is the site of digestion and absorption of nutrients. It is adapted well to enable the effective absorption of nutrients from the digested food. It is adapted with greater length and less width that causes slow movement of food which gives enough time for absorption, it has larger numbers of villi which increases the surface area for absorption, and single-cell epithelium helps in easy transport of nutrients across the epithelial layer.