@ Dr. Heinz Lycklama
Mass of Proton
nMass of proton is chosen for stability
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
Evidence of a precise design!