Aswitch is used to start the flow of current in an electrical circuit, and with switch closed, electricity flows through wires, switch and bulb, to light up the bulb. Given these facts, what powers a light bulb among the following options:
- structure and function
 - The tungsten filament
 - photosynthetic pigments?
 - Unplugging a lamp
 - heat production
 - heat is produced
 - Unscrewing a light bulb
 - The flow of electrical current


 

        The flow of electrical current 