If the world got populated from the start by two people then how did we get difference races?
The human population never reached such a bottleneck, so that question is completely meaningless and irrelevant.
adaptation of the peoples. they adapted to their environments.
Yes, actually, that is basically how we get different races. I say basically because "adaptation" alone doesn't necessarily explain the differences between races, although it does to a certain extent. I doubt that its solely of natural selection. If I remember correctly, in The Third Chimpanzee, Jared Diamond argues that a large part of the differences between races may be due to sexual selection (which is of course a form of natural selection of "adaptation," it's just that the environment consists of what potential mates find attractive). Of course, random factors like genetic drift also probably played a role.
well, maybe God made more people after he exiled adam and eve from the garden? thats logical, i guess.
No, it's not logical. I see no logic in that claim. If it wasn't for the fact that Vulcans rarely show their emotions, Spock would be facepalming at this sentence. Nothing in the Bible indicates this. And nothing in reality indicates that God created Adam, Eve, or the Garden of eden in the first place.
but for the most part we are all related. but none of the relationships are incestuous.
Actually, this is almost correct, but not quite. Take out for "for the most part" and you'll be fine. We are all indeed related. And most relationships are not incestuous despite this because incest is defined as a sexual relationship between close kin. Most people do not have sexual relations with their close kin, but there distant cousins.
