Question

Why are bacteria and fungi called decomposers?

Answer 1

Hint: They play a critical role in the flow of energy through an ecosystem. They are organisms that break down dead or decaying organisms into simpler organic or inorganic matter. If they were not in the ecosystem, the plants would not get important nutrients.

Complete answer:
Bacteria and fungi are called decomposers because they break down the dead and decaying organic matter into simpler substances such as carbon dioxide, water, simple sugars, and mineral salts and provide the nutrients back to the soil. The advantages of decomposers to the environment are that they act as natural scavengers (an animal that feeds on carrion, dead plant material,) and they also help in recycling nutrients.

Additional Information
The decomposer is thought of as a primary source of litter and or waste in the ecosystems.
Fungi have been studied to make a selection of prescription drugs along with many other antibiotics. Most saprotrophic fungi expand as a separate network of hyphae.
Moreover, only wood-decay fungi have evolved the enzymes necessary to decompose lignin which is a chemically complex substance found in wood.
Hyphae (a long, branching filamentous structure of a fungus) used to break down substances and absorb nutrients. They are also used in reproduction, when two compatible fungi hyphae grow close to each other, they will then fuse together for reproduction and form another fungus.

Note: Decomposer and detritivores both obtain nutrients by consuming detritus, both the terms are often parallel used. Both the term means differently. Detritivores ingest and digest dead matter internally, whereas decomposers directly absorb nutrients by external chemical and biological processes.