Two iron rods are placed horizontally, touching end-to-end. one end of one rod is heated. after some time, the other rod also feels warm to touch. how did the heat travel from the heated rod to the one that was not heated? a) the air over the heated rod traveled to the other rod and made it warm. b) part of the heat was converted to radiation and traveled to the cooler rod. c) electrons within the rods started moving, distributing heat consistently in both rods. d) the molecular movement in the first rod transferred energy to the molecules in the second.