recently at school we have been learning about microbes there are five types of microbes , bacteria ,virus, fungi, Archean and algae we are learning are only learning about fungi ,viruses and bacteria. Fungi is the biggest microbe and viruses are the smallest viruses are not free living the need another living living cell i order to survive bacteria is free living so they do not need a host to survive microbes are microscopic and cannot be see by the eye alone. bacteria lives every where in water in the air and even on your skin. most bacteria is harmless but some can cause disease.