Hello I have a few questions regarding evolution. 1- if short stature equals better heat retention why are people from Europe (Russia for example) usually taller statistically. 2- why haven't native Americans developed white skin since the also lived in colder climates. 3- and this is the one I struggle with the most and it's probably because I'm misunderstanding something, evolution is a very slow process that takes thousands and millions of years, shouldn't then the first advantageous mutation be so small therefore rendering it not advantageous at all?, one example that comes to my mind is webbed feet, I mean wouldn't its earliest form be so small therefore making it negligible. please don't kill me.