This is the kingdom Fungi.
Fungi are eukaryotic organisms including microscopic (like yeast) and macroscopic (like mushrooms) organisms. Their typical characteristic is chitin in their cell walls. Fungi are heterotrophs which means they cannot produce their own food, thus they absorb dissolved molecules, usually by secreting digestive enzymes into their environment. Fungi are the principal decomposers because of their ability to decompose of organic matter and thus, have fundamental roles in nutrient cycling.