Which property of a material can change its resistivity?

The property of a material that can change its resistivity is temperature. As the temperature of a conductor increases, the resistivity typically increases as well. This is due to the increased vibration of atoms within the material, which impedes the flow of electrons and thus raises the resistance. In polymers and semiconductors, the behavior can vary, but typically they show decreased resistivity with an increase in temperature due to enhanced movement of charge carriers.

While color, composition, and density can affect resistivity, they are not as directly related to the immediate physical state of the material as temperature is. Color does not have an inherent impact on electrical properties, composition does dictate resistivity, but it's not an intrinsic state change, and density typically does not influence resistivity in metals and conductors in the immediate context of resistance change under standard conditions. Therefore, temperature is the most relevant factor when discussing changes in resistivity.