How do animal cells plant cells freshwater protists and bacteria deal with osmosis?

Plant cells have cell walls that are rigid, the animal cells have flexible cell membranes, in a fresh water protists it has a contractile vacuole, in bacteria it has rigid cell wall. To maintain the cell volume after osmosis is the challenge they face.

Movement from water molecules from the region of higher concentration to a medium of lower concentration is called Osmosis. This happens through a semipermeable membrane. And this process continues till in both outside and inside the molecules are balanced.