What is the function of vacuoles in the organism of unicellular organisms?

In the cell of unicellular animals, there are two types of vacuoles: digestive and contractile. The food of the protozoa (unicellular algae, bacteria, other protozoa) gets into the digestive system, and the digestive enzymes digest it.

In the process of contraction, contractile vacuoles push out excess water and decay products dissolved in it. This is especially important for freshwater protozoa, in whose cells water enters not only during feeding, but also during diffusion.