ANSWER -;
Bacteria -:
bacteria decompose did leaves and animal and help in recycling of matter these bacteria help to return carbon nitrogen nutrients to environment they are also known as natural scavengers.
the decomposition of dead plant and animal waste result in dark layer of organic metal called humus anaerobic bacteria complete the decomposition process and thus help in keeping their environment clean. in this way bacteria is very important for environment.
Fungi-:
fungi are saprophytic in nature they help in decomposition of plant and animal waste help in recycling nutrients and help in cleaning environment along with bacteria fungi convert dead tissue of plant and animal into simple substance mineral and gases they help in cleaning and government as the mineral again used in plant.
in this way fungi and bacteria are very important for environment and they clean environment and called natural scavengers.