Lichens are complex organisms formed from a symbiotic relationship between fungi and photosynthetic partners, usually algae or cyanobacteria. They thrive in various environments, often on rocks, trees, and soil, and are known for their ability to survive extreme conditions. Lichens play an essential role in ecosystems by contributing to soil formation, serving as bioindicators of environmental health, and providing habitat and food for various organisms. Their unique structure allows them to absorb moisture and nutrients directly from the air.