In physics, there are different quantities that are conserved: in an undisturbed system the sum of these quantities is the same before and after a process. Four of these quantities are electric charge , energy, momentum and spin .
There are also quantities that stay conserved in some processes, for example flavor that is conserved by every force except the weak force.
Read more about the conservation laws on the main page.
About Conservation Laws in German. (Erhaltungssätze)