Answer:
The statement that best describes insulators is "Electrons within their atoms are strongly held by the nuclei"
Step-by-step explanation:
Atoms are constituted by a nucleus with positive charge (protons and neutrons), around which negative charges (electrons) revolve.
Substances that have a huge amount of "free electrons" that can move through the material are called conductors. This is due to the low resistance to the movement of the load or electric current.
Materials that do not conduct electricity are called insulators. In this case the electrons are strongly bound to the nucleus and cannot move freely. In this way a great resistance to the flow of electric current is offered.
Finally, semiconductors are the materials that can have electrical properties of conductors or insulators.
So the statement that best describes insulators is "Electrons within their atoms are strongly held by the nuclei"