If an incandescent light bulb converts electricity into light by sending electricity through hair-thin fibers of glass, then an incandescent light bulb converts electricity into light by sending electricity through what?

Answer choices:
- hair-thin molecules
 - hair-thin spokes
 - epidermis and dermis
 - hydrogen and oxygen
 - activation energy
 - an electron lens
 - hair-thin hairs
 - hair-thin fibers of glass

 

        hair-thin fibers of glass  