photosynthesis

Lichens make their own food from their photosynthetic parts and by absorbing minerals from the environment. The fungus lives in a symbiotic relation with the algae. The fungus benefits from the algae or cyanobacteria because they produce food by photosynthesis. The algae or cyanobacteria benefit by being protected from the environment by the filaments of the fungus, which also gather moisture and nutrients from the environment, and provide an anchor to it.