$7\mathrm{.}11*$ Figure $7\mathrm{.}11$ shows a pressure versus temperature phase diagram for a system exhibiting two solid$-$state phases. Sketch the Gibbs free energy curves versus temperature for the two solid phases and the liquid phase. Comment on the slopes of the curves.

$($Please sketch the Gibbs free energy curves versus temperature at $P=1$atm. The Gibbs free energy curve for the vapor phase is optional.$)$

Figure $7\mathrm{.}11$