I believe it is the dependent variable b/c it is the thing(s) that is been observe or measure
Neutron, neutral subatomic particle that is a constituent of every atomic nucleus except ordinary hydrogen. It has no electric charge and a rest mass equal to 1.67493 × 10−27 kg—marginally greater than that of the proton but nearly 1,839 times greater than that of the electron.
Answer: Charles's law, Avogadro's law andd Boyle's law.
Charles law states the constant ratio of volume to temperature, at constant pressure. Boyle's law states the constat product of pressure and volumen at constant temperature. Avogadro's law states that equal volumes of gases at the same temperature and pressure have equal number of particles.
So, all those three laws combined state the relation of pressure, volume, temperature and number of particles of a gas, which is what the ideal gas law does: PV = n RT.