It has the units of Joules, and it is represented by delta G. So in equation four, if we rewrite this term with delta G, we basically get equation five. And this is the equation that gives us the Gibbs free energy when a process takes place. Now, if we look at equation three and we look at equation one, so we know from the second law of thermodynamics that in any real biological process, the change in entropy of the universe must always be a positive value. So after the reaction takes place, the energy must be more dispersed and more spread out than before that reaction actually took place. And what that means is, for this to actually be true, the right side of the equation, the delta S of the universe, must always be a positive value, right? So this is the same thing as saying this.