Which of the following is true about the relationship between current and voltage in a series circuit?

In a series circuit, the key characteristic is that the current remains constant throughout all components. This means that the same amount of electrical charge flows through each part of the circuit in a single pathway. The voltage, however, varies across the components of the circuit based on their individual resistances.

According to Ohm's law, the voltage drop across a resistor in a series circuit is directly proportional to the resistance of that resistor. Therefore, while the current stays the same, the total voltage supplied by the power source is divided among the various resistors or other components in the circuit. This results in different voltage readings at different points in the circuit, dependent on the resistance of those components.

Thus, the relationship highlighted in the correct answer emphasizes that the current is constant in a series circuit, while the voltage can change depending on the resistive elements present. This fundamental concept is critical in understanding the behavior of electrical circuits and ensures that practical applications follow consistent electrical engineering principles.