A student made a graph to show chemical equilibrium position of a reaction. The student forgot to label the y-axis of the graph. A graph is shown with two graph lines. One graph line starts at a higher position on the y axis and slopes downwards towards the right. The other graph line starts at a lower position on the y axis and slopes upwards towards the right. The two graph lines meet and continue as a straight line parallel to the x axis. A vertical line is shown at a point where the two graph lines first meet. This vertical line is labeled equilibrium. The title on the x axis is Time and an arrow pointing towards the right is shown above Time. The title on the y axis is left blank. What best explains the label that the student should use on the y-axis?