And this is a result of the electric forces that exist in nature both positive or both attractive and repulsive electric forces. So let's suppose we look at situation three. In situation three, we have six C molecules that each have a positive one charge. And on the other side, the right side, we have 6D molecules that each have a negative one charge. Once again, we are separated by a semipermeable membrane that allows both of these molecules to pass through. So in this case, molecule C has a positive charge and molecule D has a negative charge.