Which electrical properties does Ohm's Law relate and how?

Ohm law states that the potential differnce between two points in a conductor is directly proportional to the current through those points (multiplied by the resistance)
I.e., V=IR
This makes sense when you consider a simple circuit. If you applied a potential difference to a parallel circuit with different resistance on each path, you would expect more current to pass through the path with lesser resistance. This is predicted by Ohm's law.