A light bulb is used for seeing in the dark.
Conventional light bulbs generate light by heating a filament.
Heating a filament is helpful for seeing in the dark.
What is helpful for seeing in the dark?
a: an electron microscope
b: an electron lens
c: microscope
d: closing the blinds
e: blackouts
f: closing your eyes
g: focusing a lens
h: heating a filament