sentences: conductivity is a property of a material & conductivity is a kind of physical property ->  conductivity is a physical property of a material  conductivity is a physical property of a material & copper is a kind of material ->  conductivity is a physical property of copper  metal is an electrical / electrical energy conductor & copper is a kind of metal ->  copper is an electrical conductor  conductivity is a physical property of copper & copper is an electrical conductor -> the ability to conduct electricity is a property of copper