The origin of neutrino mass: Stations along the path of cognition

I propose to give an outline based on partial answers to questions beneath 'the origin of neutrino mass':

(a) building on the limiting uncurved structure of 1 time + 3 space dimensions, what is the full extent of space-time dimensions and their meaning in quantum gravity? (b) what is the origin and nature of spin-½ fermions? (c) if charge-like and orientation-like gaugeing is related, then what is the explanation for 3 colors and 3 families along the path of unification?