  I discuss the use of neutrinos from the CN cycle and pp chain to constrain
the primordial solar core abundances of C and N at an interesting level of
precision. A comparison of the Sun's deep interior and surface compositions
would test a key assumption of the standard solar model (SSM), a homogeneous
zero-age Sun. It would also provide a cross-check on recent photospheric
abundance determinations that have altered the once excellent agreement between
the SSM and helioseismology. Motivated by the discrepancy between
convective-zone abundances and helioseismology, I discuss the possibility that
a two-zone Sun could emerge from late-stage metal differentiation in the solar
nebula connected with formation of the gaseous giant planets.
