Earlier quoted context omitted.
Points 1 2 and 4 are pretty well studied in academia concerning intelligence. Intelligence is defined as "g", and it's 60 to 80% heritable depending on the study (leaning towards 80%). More info for the curious: https://en.wikipedia.org/wiki/G_factor_(psychometrics)
It's easy to misunderstand what heritable or even genetically heritable means. Consider just few hypothetical ways genes can increase g-factor: * Metabolic trait increases nutrition intake in high calorie low nutrition junk food environment. This leads to faster brain development. * Improved immune system against certain parasites that makes individual healthier and leads to statistically higher g-factor. Genes that…
Anyway, I don't understand how this is supposed to explain what heritability is...