What is a common measure of a material's opposition to electric current flow?

The appropriate measure of a material's opposition to electric current flow is Ohms. Ohm's Law defines this relationship, where resistance (measured in Ohms) quantifies how much a material resists the flow of electric current. In this context, if a material has a high resistance value in Ohms, it indicates that it is more challenging for electric current to pass through it.

Volts measure electrical potential or voltage difference, Watts measure power (the rate at which energy is consumed or produced), and Amperes measure the flow of electric current. Each of these units serves a different purpose in electrical engineering and circuit analysis, but none quantify resistance like Ohms do. Therefore, Ohms stands out as the correct answer in identifying a material's opposition to electric current flow.