One example of animals having a single opening to the outside that serves both as mouth as well as anus is

One example of animals having a single opening to the outside the serves both as mouth as well as anus is

Read the following statements Organ systems in different group of animals show various patterns of complexities. The digestive system in Platyhelminthes has only a single opening to the outside of the body that serve as both mouth and anus, and is hence called complete. In open type of circulatory system, the blood is pumped out of the heart and the cells and tissues are directly bathed in it. In closed type, the blood is circulated through a series of vessels of varying diameters (arteries, veins and capillaries). Which of the following statement(s) is/are correct?

Give examples of animals having open type of circulation.

Animal having tentacles around mouth.

The group of animals having open circulatory system is

Give one example of an animal that can live both in water and on land.

Which organism have a cavity (gullet) that opens to the outside of the cell surface?