Why does a gas fill the container completely ?

Why does a gas gets heated on compression?

Explain with the help of kinetic theory, why pressure of a gas in its container walls rise when volume is reduced?

Why does an object fall down ?

Why does a tank filled with water appear shallow?

Consider two containers A and B containing identical gases at the same pressure, volume and temperature. The gas in container A is compressed to half of its original volume isothermally while the gas in container B is compressed to half of its original value adiabatically. The ratio of final pressure of gas in B to that of gas in A is