Decomposers are living beings directly involved in the decomposition of dead organic matter (necromass) or excrement or excreta of living beings of different trophic levels.
The four trophic levels (with examples) are:
*Producers, such as herbs and algae.
*Herbivores, such as rabbit and sheep.
*Primary carnivores, such as wolves and eagles
*Secondary carnivores, such as lions and bears