If you have, then you've eaten plant material. Trees and green plants make food for you and other animals. Worms, snails, and mushrooms are breakers, or decomposers. They feed on animals and plants that are dead. This may sound disgusting, but it's very important.
Breakers give the makers nutrients.
The makers use the nutrients to grow bigger and to make new food. Color the makers green, the eaters orange, and the breakers brown. Dead trees don't have any leaves. Their bark may fall to the ground. Most people harvest, or cut down, dead trees.