Science help please?!?

Autotrophs make their own food (plants and algae). Heterotrophs (animals) consume the food made by autotrophs - or consume other animals that consumed animals that consumed autotrophs. Decomposers, primarily bacteria and fungi, break down the complex substances in dead animal and plant tissues into simple substances that autotrophs can then absorb and use to produce more food. Prey animals always outnumber predators. Otherwise the large number of predators would quickly wipe out the smaller number of prey animals, and the predators would then quickly die off as well.