Fact 1: Viruses are so small that they can be seen only with an electron microscope.

Fact 2: Viruses are studied by radiography and use of the electron microscope.

Given the two facts above, answer the question "What is used to study viruses?" with the following options: 
- rays or beams
 - Cooking
 - aqueous solution
 - energy
 - an image
 - radiation
 - radiography
 - Dilution


 

       radiography  