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

Fact 2: Viruses Viruses are very small, a few nanometers in size.

Given the two facts above, answer the question "Objects that are a few nanometers in size can be seen only with:" with the following options: 
- an electron microscope
 - refraction of light
 - matter vibrating
 - ultrasound
 - The bending of a ray of light
 - slight magnification
 - flashlights
 - lens


 

 an electron microscope        