Micro-organisms are those organisms that are not visible through the naked eye.
They are classified into two categories :-
1. Unicellular organism - They are consists of a single cell. This means all life processes such as reproduction, feeding, digestion, and excretion, occur in one cell. Some examples of unicellular microbes are amoeba and bacteria.
2. Multicellular organism - They are composed of more than one cell as compared to unicellular microorgannisms.Almost all species of animals, plants and most fungi are multicellular in nature.
Furthermore,
Microorganisms are divided into seven types:
1 .Bacteria
2. Archaea
3. Protozoa
4. Algae
5. Fungi
6. Viruses
7. Multicellular organisms
Each type has their unique characteristic fearures such as its cellular composition, morphology, mean of locomotion, and mode of reproduction