Mycorrhizal fungi are special kinds of fungi that live in soil. They form partnerships with plants and help plants get nutrients and water from the soil. When mycorrhizal fungi are connected to plant roots, they can also help the plant store more carbon, a type of energy, in the soil. The carbon is stored in the form of a material called humus, which is made up of decayed plants and animals. So when mycorrhizal fungi are present in the soil, it can help keep more carbon from entering the atmosphere and causing global warming.