Fungi

Fungi (kingdom Fungi) are heterotrophs. They cannot manufacture their own food as photosynthetic organisms can.
Most species of fungi are saprotrophic; they decompose dead matter. Many are parasitic; they obtain nutrients from living organisms.
Fungi are the principle decomposers in every ecosystem. They can break down most organic compounds including lignin, a compound that is a major component of wood and is very difficult to break down or digest.
Some species are parasites and others are mutualistic.
They have extracellular digestion by secreting enzymes into environment and absorbing the nutrients produced.
Fungi store their food as glycogen (like animals). Plants and green algae store their food as starch.