Which material does not allow heat or electrons to move through it easily?

The material that does not allow heat or electrons to move through it easily is an insulator. Insulators are designed to inhibit the flow of electricity and thermal energy. This characteristic arises because insulators have tightly bound electrons that do not move freely, which prevents them from conducting electricity. Additionally, insulators are effective in preventing heat transfer, making them ideal for applications where maintaining temperature is crucial, such as in thermal insulation in buildings or in electrical wiring to prevent shocks.

In contrast, conductors are materials that allow heat and electricity to flow freely due to their loosely bound electrons. Semiconductors have properties that fall between those of conductors and insulators and can conduct electricity under certain conditions. Resistors are components that limit the flow of electric current but do not necessarily serve the purpose of insulating from heat or preventing electricity from passing through, as they are specifically designed to create resistance in a circuit. Thus, the defining features of an insulator make it the correct choice for this question.