Answer
The junction rule: Law of Conservation of Charge.
The loop rule: Law of Conservation of Energy.
Work Step by Step
The junction rule states that the current entering any point in a circuit must equal the current leaving that point. Otherwise, charge would either build up or disappear from a circuit.
So, the junction rule is based on the Law of Conservation of Charge.
The loop rule states that the net change in electric potential must be zero around any closed loop. This is analogous to gravitational potential energy, and is based on the Law of Conservation of Energy.
