Abundance of Sc vs. log T at the time the SCZ becomes stable for the 1.5 (solid curve), 1.7 (dashed curve), and 2 M_⊙ (dash-dotted curve) models, expressed as the difference between the logarithm of the current ratio to H in number fraction and the corresponding initial value. The vertical lines with the same curve style denote the location of the bottom of the surface convective zone. These results are for models with convection as the unique mixing process and with no mass loss.