Which is a postulate of the kinetic-molecular theory?
1.gas particles have a small volume relative to the spaces between them.
2.gas particles have a large volume relative to the spaces between them.
3.gas particles are very small in size and always move slowly.
4.gas particles are very large in size and always move slowly.

1.  Gas particles have a small volume relative to the spaces between them

Explanation:  Kinetic-Molecular Theory is the theoretical model which studies the interaction of molecules and particles which helps us in understanding the ideal gas law.

Its first postulate explains that the gas particles have very small volume that is negligible in comparison to the volume of the container in which the gas has been filled.

Thus , gas particles have a very small volume relative to the spaces between them