The correct answer to the question is - oppose the flow of current through substances.
EXPLANATION:
From Ohm's law, we know that current [ I ] flowing a wire is directly proportional to the potential difference [ V ] maintained across the two ends of the conductor at constant temperature and pressure.
Mathematically V ∝ I .
⇒ V = IR .
Here, R is the proportionality constant called resistance of the wire.
From above, we see that current flowing through a wire is inversely proportional to the resistance. It means that the current flow will be less with the increase of resistance of the wire.
Hence, resistance can be defined as the opposition to the flow of current in an electric wire.
