Fungi or mushrooms are the fruiting body of the mycelium network.
Fungi decompose and absorb a huge variety of nutrients and elements. In doing so they produce fertile soil, naturally carry out the process of carbon capture and with there symbiotic relationships with many plants and trees also help lock even more carbon into the plant structure, by helping them grow quicker.
The mycelium spreads out through the soil and other organic materials to help breakdown and assimilate compounds. In fact mycelium grows into such an intricate network, left untouched by human intervention fungi can become the largest organisms on this planet.