Microorganisms, or microbes, are tiny living organisms that can only be seen with a microscope. They are also known as microorganisms or microscopic organisms as they could only be seen under a microscope. They make up almost 60% of the earth's living matter. This diverse group includes bacteria, viruses, fungi, algae and protozoa. Everywhere on earth, including soil, water, the atmosphere, animals, plants, and humans, is home to microorganisms. The atmosphere is the only place where microbes cannot proliferate. All other living cells on our planet pale in comparison to their collective number. Microbes can be useful as well as harmful.