在自然界的生物中,除了动物和植物外,还有一部分必须借助于光学显微镜或电子显微镜,放大几百倍甚至几万倍才能观察到的微小生物,称微生物。微生物的种类繁多,它们的绝大多数对人和动物是有益或无关的;少数能够引起病害,这些具 Among the creatures in nature, in addition to animals and plants, there are also microbes that must be observed with the aid of light or electron microscopes, magnified several hundred times or even tens of thousands of times. A wide range of microorganisms, most of them beneficial to humans and animals or irrelevant; a few can cause disease, these