sentence2_structure: You<>call<>materials able to conduct electricity with 100% efficiency
sentence1: There is no electrical resistance in a superconductor, and therefore no energy loss.
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?