What part of the microscope allows you to change the amount of light coming to your slide?

For those who need theses answers i just took the test and got everyone of them

Being able to see a square in the middle of the image despite not having lines to form a square represents the gestalt principle of a. proximity b. similarity c. closure d. continuity

In an electric circuit, what is one material that the connector can be made of? a. rubber b. aluminum foil c. glass d. wood