Question:Which Of The Following Would Double The Amount Of Current Flowing Through A Piece Of Metal Wire?

The resistance of  your  wire (conductor)  increases with increase in temperature because the temperature come with heat which increase the  vibration of atoms , this causes many collision between the free electrons and the bounded electrons , each collision use up some energy from the free electrons and is the basic cause of resistance,  the more the atoms jostle around in the material , the more collision are caused and hence the greater to current flow. Sources