Buding (also called burgeoning) is the formation of a new organism by the protrusion of part of another organism. This is very common in plants and fungi, but may be found in animal as well, such as the Hydra. Usually, the protrusion stays attached to the primary organism for a while, before becoming free. The new organism is naturally genetically identical to the primary one (a clone). When yeast buds, one cell becomes two cells. When a sponge buds, a part of the parent sponge falls off and starts to grow into a new sponge. These are examples of asexual reproduction.