It includes molecules, atoms, fundamental particles, and any substance that these particles make up. Matter can change form through physical and chemical changes, but through any of these changes matter is conserved. The same amount of matter exists before and after the change—none is created or destroyed.

Can be matter be created?

Matter makes up all visible objects in the universe, and it can be neither created nor destroyed.

Can matter create itself?

Every interaction between particles that we've ever observed, at all energies, has never created or destroyed a single particle of matter without also creating or destroying an equal number of antimatter particles.