What is true regarding insulators?

Insulators play a crucial role in electrical systems by restricting the movement of electrons. This property is fundamental to their function, as they prevent unwanted flow of electricity, thereby protecting both components of a circuit and ensuring safety for users. Insulators are typically made from materials such as rubber, glass, or plastics, which have tightly bound electrons that do not easily move. Consequently, they act as barriers to electron flow, contrasting with conductors, which facilitate mobility of electrons.

The other options provide incorrect definitions or characteristics of insulators. For example, conductors are specifically designed to allow the free flow of electrons, making the idea of insulators facilitating movement untrue. Similarly, insulators do impact the flow of electricity by inhibiting it, rather than having no effect. Additionally, while insulators can also have properties that limit heat transfer, they are not classified as conductors of heat, which is a property associated with materials that allow thermal energy to pass through them readily. Thus, the understanding of insulators as materials that restrict electron movement is essential for grasping the basics of electrical circuits and safety.