Which protozoan in unlikely to have a contractile vacuole

Which protozoan is unlikely to have contractile vacuole ?

Amoeba has a contractile vacuole for

A biologist was experimenting with a protozoan and noticed that the animal's contractile vacuole stopped working although the other parts of the organism seemed to be in good health and exhibited normal activity. Which of the following experiment was likely to have produced this result?

The main function of the contractile vacuole is :

In Amoeba , contractile vacuole is present

In Amoeba , contractile vacuole is present

What is the function of contractile vacuole?

In Amoeba , contractile vacuole is present