what is a microorganism
A microorganism or microbe is an organism which is too small to be seen by the unaided human eye. They are microscopic. The study of microorganisms is called microbiology. Microorganisms include bacteria, fungi, archaea or protists and viruses.The first four types of microorganisms may be either free-living or parasitic. Viruses, however, always reproduce inside other living things.icroorganisms live almost everywhere on earth where there is liquid water, including hot springs on the ocean floor and deep inside rocks within the earth 's crust. Such habitats are lived in by extremophiles. Microorganisms are critical to nutrient recycling in ecosystems, because they act as decomposers.
but this term only describes relatively few microorganisms. All microorganisms are living things or organisms. Microorganisms may be unicellular or single-celled, any living thing that has only one cell, the smallest unit of life. Some microor-ganisms are multicellular, having more than one cell. Microorganisms require food, air, water, ways to dispose of waste and an environment in which they can live. Some microorganisms are producers, living things that make their own food from simple substances usually using sunlight, as plants do. Some microorganisms eat other organisms to get their food. Most microorganisms