yea, as in being created. a car doesnt exist as a car until its put together, but there isnt a fixed amount of cars in the universe. matter may not be able to be created or destroyed, but not only does every molecule break apart and react to become different substances (C + O2=>CO2=>C+O2), but the neutrons, protons, and electrons are constantly being exchanged. for example, i just increased the amount of CO2 in the universe because i made a CO2 producer two hours ago