When two or more organisms live together in such a way that both benefit from this association, it is called Symbiosis. Organisms involved in association are called Symbionts.
Lichen is a Symbiotic organism. He lives with Cyanobacteria and fungi. It supports the fungus and absorbs water. While Cyanobacteria makes food for both. This type of Symbiosis is called Mutualism.
