Budding has the advantage of not weakening the original cell. Sometimes more than one bud can be formed at a time and more new cells can be produced quickly under excellent conditions. Protozoans form cysts when it becomes too cold or too dry. The cysts are formed when the cell walls thicken and becomes hard like a shell. The insides of the cells are kept alive in a sort of suspended animation.
Cysts can travel to other ponds on the wind or on the feet, feathers or fur of large animals.
Some even travel in the digestive organs of larger animals. When conditions are warmer and wet enough, the cyst wall dissolves and the protozoan starts growing and feeding again. The commonest protozoans in a pond are amoeba, mastigophora, paramecium and suctoria.