In a parallel circuit, what remains constant across all resistors?

In a parallel circuit, the voltage across all resistors remains constant. This is due to the way parallel circuits are structured, where all components share the same two nodes. Therefore, every resistor connected in parallel experiences the same potential difference, which means that they are all subjected to the same voltage.

This property of parallel circuits is crucial for understanding how they function, as it allows each resistor to operate independently of the others regarding the amount of current flowing through it. The total voltage remains uniform, while the individual currents through each resistor can vary based on their resistances. Thus, the correct answer highlights a fundamental characteristic of parallel circuits that is essential for analyzing their behavior in electrical systems.