The heavier the material, the ______ efficient it is as a conductor?

The statement highlights the relationship between the weight of a material and its effectiveness as a conductor of electricity. In general, heavier materials tend to have a higher density, which often correlates with a greater number of free electrons available for conduction. This is crucial in conductive materials, as the mobility of these electrons is key to efficient electrical conduction.

Metals, for example, are typically heavier and are known to be excellent conductors because they have a structure that allows for a high degree of electron mobility. Thus, the heavier the conductive material, the more efficient it typically is, as its atomic structure supports better conductivity through increased electron flow capability.

In contrast, lighter materials may not have the same density or electron availability, resulting in lower conductivity. Hence, the correct completion of the statement accurately reflects the underlying physics of electrical conduction.