If wiring requires the opposite of an insulator, then what is absolutely required for wiring to work?

Answer choices:
- increases a body's strength
 - heat is produced
 - The opposite of an insulator.
 - Something that comes in a bundle of fibers
 - quart or nickel plated aluminum
 - To another location like underground
 - underground systems
 - Time and energy

 

   The opposite of an insulator.       