what is fungi

Fungi (singular fungus) are a kingdom of eukaryotic organisms. The fungi are heterotrophic organisms characterized by a chitinous cell wall, and in the majority of species, filamentous growth as multicellular hyphae forming a mycelium; some fungal species also grow as single cells. Sexual and asexual reproduction is via spores, often produced on specialized structures or in fruiting bodies. Yeasts, molds, and mushrooms are examples of fungi. Fungi are more closely related to animals than plants, yet the discipline of biology devoted to the study of fungi, known as mycology, often falls under a branch of botany.
Occurring worldwide, most fungi are largely invisible to the naked eye, living for the most part in soil dead matter and as symbionts of plants, animals, or other fungi. They perform an essential role in all ecosystems in decomposing matter and are indispensable in nutrient cycling and exchange. Some fungi become noticeable when fruiting, either as mushrooms or molds