I have several questions. =]

What great geological event explains the formation of the Great Lakes, the St.Lawerence River systen,the Columbia-Snake River system and Great Salt lake?

How di this same geological even isolate the human population of the Americans from that of Asia?

Given the original geographical orgins of the Idian populations, in which direction did their earliest migrations across North America occur: from southest to north and west, from southwest to north and east or from northwest to south and east?

ps.how do you all FIND the answers to these questions.. it would be a big help! =]

1. Ice age glacier movement.
2. Bearing Straight forming then melting.
3. If the Idian are the ones that came across the Strait, then it's northwest to south and east.

You can probably wikipedia all this.