Fungi are eukaryotic organisms that are unicellular or multicellular.
Decomposition is a process of breaking down complex organic matter into inorganic compounds. The organisms that help in decomposition are called decomposers.
Fungi are decomposers. They produce exoenzymes that degrade organic matter.
While decomposing organic substances, essential nutrients such as nitrogen, phosphorus, and sulfur are released which can be used by living organisms.
Example- White rot fungus uses strong enzymes to break down lignin present in the wood into simpler carbon dioxide and sugars.