Out of the following given choices;
A. the size of the atoms in a substance
B. the number of molecules in a substance
C. the position of the electrons on the outer valence shells
D. the balance between intermolecular forces and kinetic energy
The answer is D. The kinetic energy of the molecules is determines by the temperatures of the substance. The higher the temperatures, the higher the kinetic energy of the molecules. The molecules subsequently move and collide with higher energies and overcome intermolecular forces. This allows the substance to changes state from solid to liquid and eventually to gas (with increasing kinetic energy).