Fact 1: An electron microscope is used for seeing very small objects by making them appear bigger.

Fact 2: Electron microscopes use a beam of electrons as their source of illumination.

Given the two facts above, answer the question "To make very small objects appear bigger, one can use what instead of light for illumination?" with the following options: 
- electricity
 - electron beam
 - by indirect light
 - reflecting light
 - photons
 - Electrical energy
 - heat energy
 - mirrors


 

  electron beam       