What are microorganisms?

Microorganisms are very tiny living things. They are so small that you need a microscope to see them.

Microorganisms are all around us, in the air, in our bodies and in water. Some microorganisms are harmful to us, but others are helpful to us.

There are three types of microorganism:

• viruses

• bacteria

• fungi

Harmful microorganisms

Some diseases, like…