copper wires are widely used for _____ because they are _____ and are good conductors of electricity while still and _____ are good conductors of both _____ and _____ conductors are metals that allow electricity and heat to _____ freely through them _____ electricity and heat to be transferred from the source through them not all materials are good conductors of heat and electricity materials that are _____ or that _____ heat and electricity to pass through them are called _____​