They're so small you can't even see them. They multiply faster than the clothes that keep piling up on your floor. They're everywhere they lurk in the water you drink, the food you eat, and the air you breathe. At this very moment they are in your stomach and on your skin. What's more, they've been around forever. Sound like creatures from a horror movie? Nope! They are germs or, more scientifically, microbes. And there is more than one kind of microbe out there. Viruses, bacteria, fungi, and protozoa all qualify.