The formation of a steady state in an ORN can be explained as due to the achievement of a full balance between all the involved reaction and diffusion processes under constant inflows and outflows of chemical substances, as mentioned in the Results section. This mechanism can be explained as follows. The time evolution of an ORN toward a steady state is described by the same reaction kinetics as that of a closed reaction network toward an equilibrium state and hence a steady state of an ORN is stabilized in the same way as an equilibrium state. In fact, in both cases, reaction and diffusion processes follow rate equations such as equations ( ) and ( ) and are always forced to approach equilibrium. In addition, in both cases, such reaction and diffusion processes are mutually linked with each other by reaction equations and rate equations. Therefore, for a closed reaction network, these processes finally reach an equilibrium state in which they have attained a full balance. Similarly, for an ORN, they reach a non-equilibrium steady state in which they have approached equilibrium to the largest extent possible under constant inflows and outflows of chemical substances and have attained a full balance, if no oscillatory or dispersive behavior emerges. This is because concentration changes due to irreversible reaction and diffusion processes continue to occur until these processes attain a full balance. Achieving a full balance between all the involved irreversible reaction and diffusion processes in an ORN ensures the attainment of a non-equilibrium steady state, and vice versa.