A microscope is a very powerful magnifying glass. The entire world - our bodies included - are made up of billions of tiny living things that are so small you can't see them with just your eyes. But with a microscope, it's possible to examine the cells of your body or a drop of blood. By using a microscope to see these things up close, a doctor can spot cancer cells, bacteria, and other problems that could be causing a person's illness.
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