Evolutionary benefit of animals with complete digestive tube

Question

State some of evolutionary advantages of the animals having complete digestive tube?

Answer 1

Complete digestive tube permits animals to continuously feed themselves without waiting for the residuals to get removed before beginning the digestion of new foods. This has allowed the absorption of larger amount of nutrients and hence higher and more complex species can originate. Digestive tubes having two openings can also make digestion more efficient as they offer different sites with different chemical and physical conditions (bowels, mouth, stomach,) for the action of different complementary digestive enzymatic systems.