When a second identical bulb is added in series to a circuit with a single bulb the resistance of the circuit?

When a second identical bulb is added in series to a circuit with a single bulb, the total resistance of the circuit increases. This is because the resistance of each bulb adds together, resulting in a total resistance that is double that of a single bulb. Consequently, the overall current flowing through the circuit decreases, as per Ohm's Law (V = IR), assuming the voltage source remains constant.