Why do protists need contractile vacuoles?

Contractile vacuoles:

1. Contractile vacuoles are specialized in order to regulate the water content of cells.
2. It is spherical in shape and collects excess fluid from the cell and empties it outside.
3. It is pivotal in maintaining the cell's osmotic pressure.
4. Protists are unicellular eukaryotes that exist in aquatic and damp environments.
5. Protists lack a cell wall and thus soak up excess water from their surroundings and thus contractile vacuoles are crucial in order to drain them out.