A) centimeter.
B) decimeter.
C) micrometer.
D) millimeter.
E) nanometer.

A) It allows light to travel at a uniform speed on its way to the lens.
B) It decreases the working distance.
C) It increases the numerical aperture.
D) It increases numerical aperture and maintains a uniform light speed.
E) It increases the angle of refraction of the light.

A) fluorescent.
B) confocal.
C) phase-contrast.
D) scanning tunneling.
E) bright-field.