Energy can be transformed from one form to another. In a closed system, the total amount of energy is always the same. Matter is made up of small particles, called atoms, that are in constant motion. Atoms are made up of subatomic particles including electrons, protons and neutrons. Some atoms have heavier unstable nuclei that decay spontaneously.
Evidence indicates that matter has properties of both particles and waves.
Matter can be converted to energy and energy transformed to matter. Matter and energy and their interaction govern all systems in the universe.