what is microorganisms

A microorganism, or microbe, is an organism of microscopic size, which may exist in its single-celled form or as a colony of cells. Microorganisms can be bacteria, fungi, archaea, or protists. They are found in water, soil, air, and the human body. Some microorganisms are important for our health, while others can make us sick. They are essential for various processes such as food production, waste treatment, and maintaining soil fertility. Microorganisms have been studied since the 17th century, and their scientific study is called microbiology