Microbes are tiny living beings in nature. Most of the microorganisms are not visible to our naked eye due to their size. They can be viewed under a device which magnifies sizes of minute things, known as a microscope.
There are various types of microbes namely, bacteria, protozoa , fungi and algae. Protozoa are a group of single celled microbes. E.g., Amoeba
Some microbes are useful while some are harmful to human beings. The disease causing microbes are termed as pathogens.