A microorganisms is a microscopic organisms,which may be a single cell or multicellur organisms.The study of microorganisms is called MICROBIOLOGY

Fungus(fungi) is any member of large group of Eukaryotic organisms that includes microorganisms such as Yeast and molds,as well as the more familiar mushrooms.

virus is a small infections agent that replicates only inside the living cells of other organisms.Viruses can infect all types of life form,from animals and plants to Bacteria and Archala.
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