Proposing a constitutional amendment authorizing the legislature to provide for an exemption from ad valorem taxation of part of the market value of the residence homestead of a partially disabled veteran or the surviving spouse of a partially disabled veteran if the residence homestead was donated to the partially disabled veteran by a charitable organization for less than the market value of the residence homestead or if the charitable organization donated all or part of the purchase price of the residence homestead to the partially disabled veteran and harmonizing certain related provisions of the Texas Constitution.