sentence2_structure: You<>call<>materials able to conduct electricity with 100% efficiency
sentence1: A superconductor is a material that can conduct electricity or transport electrons from one atom to another with no resistance.
sentence2: You call materials able to conduct electricity with 100% efficiency, meaning that no energy is lost during the electrical transmission, superconductors.
question: What do you call materials able to conduct electricity with 100% efficiency, meaning that no energy is lost during the electrical transmission?