Which statement would be the most useful for deriving the ideal gas law?

At constant temperature and pressure, Avogadro’s law says volume is directly proportional to the number of moles: increasing the amount of gas increases its volume proportionally. This relationship is part of the set of gas laws combined to obtain PV = nRT. Pressure is not directly proportional to volume, and volume is not inversely proportional to temperature.

AI-written and checked against the verified answer.