Before microscopes were invented, scientists thought the world was made up of only two kinds of living thingsplants and animals. But microscopes allowed scientists to see small, simple organisms no one knew existed. The discovery of these simple organisms, including germs, helped scientists discover ways to keep people healthier. For more information on simple organisms read Louis Pasteur and the Fight Against Germs, another book in the Mission: Science series. Это и многое другое вы найдете в книге Simple Organisms (Mission: Science) (Zamosky, Lisa)