There are some living things that arc very, very small so small that you cannot see them with your eyes. These very tiny living things are called microbes. You can see sotne microbes with a microscope. More than a thousand of some microbes can fit on a point of a pencil. Think of how small they are! Microbes live everywhere. Microbes float in the air, Microbes move in the water. Some microbes even grow on other living things. There are many kinds of microbes. Some are plants, some are animals. Some are so tiny that it is hard to say whether they are animals or plants. Bacteria, mold, and algae are microbes. They are all plant microbes. Protozoa are animal are microbes. smallest of all microbes is the virus. It cannot be seen with most microscopes. A special kind of microscope is used for looking at the virus. Some kinds of microbes help us in many ways. Some microbes help to make bread. The yeast microbes make the bread rise and soft. Some microbes floating in the air help to make vinegar. Not all microbes are helpful. Mold microbes can spoil food. Germs can make you catch cold. Measles and mumps are caused by tiny microbes called viruses. Now you know some microbes are helpful, some are harmful. There are many ways to stop the harmful microbes from growing, Microbes that spoil food can be kept from growing by freezing the food boiling the food. Medicine can fight microbes that make you ill.