What is a material whose electrons strongly oppose movement?

The correct answer is a material classified as an insulator. Insulators are characterized by their high resistance to the movement of electrons. This means that, in insulators, the electrons are tightly bound to their respective atoms and do not easily move when an electric field is applied.

In practical terms, because the electrons in insulators resist movement, these materials are commonly used to prevent the flow of electric current. This property is essential in various applications, such as in the insulation of wires and electrical components, where it is crucial to keep electrical currents contained within conductive pathways.

In contrast, conductors have free electrons that can move easily, allowing electric current to flow with little resistance. Semiconductors have properties that fall between conductors and insulators and can conduct electricity under certain conditions, often influenced by temperature or doping. Superconductors are materials that exhibit zero resistance to electrical flow at very low temperatures, which is a distinct and unique property far removed from the behavior of insulators.