Answer:
Volume and pressure.
Step-by-step explanation:
The gases represent the physical state of matter whose values of volume, density or shape are not defined. They have a high degree of disorder caused by the free displacement of the particles that make them up (atoms, molecules or ions - usually molecules) and are objects of study because they have great applicability in everyday life, and because they are the material layer in which we keep most contact, after all, normally our whole body is in contact with gases (atmospheric air).
The properties of the gases are variable, that is, because there are certain and specific spaces between their constituents (which can increase or decrease) the volume, density, pressure, viscosity can be changed. The smaller the container in which the gas is containing, the smaller its volume and the higher its pressure, for example.