Final answer:
The internal energy of a solid substance is primarily made up of potential and kinetic energy from vibration.
Step-by-step explanation:
The type of energy that makes up most of the internal energy of a solid substance is potential and kinetic energy from vibration. The internal energy of a solid is the sum of the kinetic and potential energies of its atoms and molecules. In a solid substance, the atoms and molecules vibrate about their equilibrium positions. This vibrational motion contributes significantly to the internal energy of the substance.