The total resistance of resistors connected in series is:

In a series circuit, components are connected end-to-end, creating a single, continuous path for the current to flow. The total resistance is found by simply adding all the individual resistance values together (R_total = R1 + R2 + R3...). Because you are adding positive resistance values together, the total equivalent resistance must always be greater than the resistance of any single resistor in that string. Every component in the series path adds an additional restriction to the current flow. The distractor stating it would be 'less than the resistance of any one resistor' specifically describes the behavior of a parallel circuit, not a series circuit.