nMass of free neutron is slightly heavier than that of a proton, and it decays to a proton, electron, and an antineutrino with a half life of 12 minutes.Free
neutrons cannot persist in nature.
nIf the mass of a proton were increased by just 0.2 %, it would decay into a neutron, a positron and a neutrino.This decay does not occur - if it did
hydrogen could not exist.Hydrogen is
the dominant element of the
universe.Without it, the universe could not exist