Electron microscopes have certain advantages over optical microscopes: The biggest advantage is that they have a higher resolution and are therefore also able of a higher magnification (up to 2 million times). Light microscopes can show a useful magnification only up to 1000-2000 times. This is a physical limit imposed by the wavelength of the light. Electron microscopes therefore allow for the visualization of structures that would normally be not visible by optical microscopy.
berm (plural berms) A narrow ledge or shelf, as along the top or bottom of a slope. A raised bank or path, especially the bank of a canal opposite the towpath. A terrace formed by wave action along a beach. A mound or bank of earth, used especially as a barrier or to provide insulation.
a germ is a microscopic organism that can carry disease other words used for germs are microorganisms microbes and in slang bugs the term generally refers to bacteria or viruses it could also include fungi or protozoa