Why is oxygen called a gas? Support your answer by giving two reasons.

(N/A) $(i)$ Oxygen has neither a fixed shape nor a fixed volume,which is a characteristic property of gases.
$(ii)$ Oxygen particles have high kinetic energy and large intermolecular spaces,allowing it to diffuse easily into the air.
$(iii)$ Oxygen exerts pressure on the walls of its container and can be compressed or liquefied under high pressure and low temperature.