Respuesta :
Because no ordinary human eye can just look at bacteria, u have to use a microscope to closely and zoom in through the scope to fully and carefully look at the bacteria.
Answer:
A phase contrast microscope uses an optical technique that works by the use of a device to read the difference in thickness of the subject affecting the phasing of light resulting in a high contrast image. Staining bacteria also help microscope users to see bacterial structures that would have otherwise been invisible to the naked eye.