Resistance in a circuit affects which of the following?

Resistance in a circuit plays a critical role in determining both voltage and current, which is why "both voltage and current" is the correct answer. According to Ohm's Law, the relationship between voltage (V), current (I), and resistance (R) is expressed as V = I × R.

This equation shows that for a given amount of resistance, the voltage across the component is directly proportional to the current flowing through it. If resistance increases, for a constant voltage, the current will decrease, and conversely, if resistance decreases, the current will increase given the same voltage.

Therefore, resistance affects how much current flows for a particular voltage level, as well as the required voltage to push that current through a certain resistance. In essence, resistance modifies both aspects of the circuit, fundamentally influencing the overall behavior of electrical components in the circuit.

The other options do not encompass the full impact of resistance. Voltage and current are interdependent because of resistance, while capacitance is a separate property related to the ability of a component to store electrical energy, not directly tied to resistance in the same manner.