Viruses are so small that they can be seen only with an electron microscope, and objects to be viewed are illuminated by electrons in an electron microscope. Given these facts, what of the following can only be viewed by illuminating electrons?  among the following options:
- insects
 - small animals
 - eyelashes
 - Light
 - an image
 - fungi
 - viruses
 - an object


 

       viruses  