Micro-organism act upon the dead plant to produce:

The correct answer is Humus. Micro-organisms act upon the dead plants to produce humus.The micro-organisms which convert the dead plants and animals to humus are KNOWN as decomposers LIKE bacteria and fungi.For the healthy soil, humus contains many USEFUL minerals and nutrients.Dead organic matter in the form of decaying plants and sometimes dead animals on the ground disappear after some time. This is because the microorganisms decompose dead organic waste of plants and animals converting them into simple substances.These substances are again used by other plants and animals.Thus, microorganisms can be used to degrade the harmful and smelly substances and thereby clean up the ENVIRONMENT.