Answer and explanation;
-The Great Ice Age created a land bridge that connected Eurasia with North America allowing nomads to come over. When the great land bridge melted it transformed the upper part of America and formed the Great Lakes.
-Early North American history was affected by the fact that the North American continent was far away enough from Europe and Asia that it was unknown yet the land bridge over the Bering Strait allowed for early peoples to migrate to the region. The climate was temperate enough in many areas that animals and crops were plentiful as well.