Due to the Force of Gravity, Which Is True About

Due to the force of gravity, which is true about the particles of a sample of gas at sea level versus those at higher altitude?

A) The atoms and molecules of a gas will move more quickly at sea level than at higher altitude.
B) The mean free path between atoms and molecules of a gas will be longer at sea level.
C) The volume of a sample of gas will be larger at sea level than at higher altitude.
D) The number of particles in a particular volume will be greater at higher altitude than at sea level.
E) The particles of the gas at sea level will be closer together than those at higher altitude.