How and why did the early people come to the America?

Answer 1

Three of the four main ancestral groups diverged from their Asian forbears at least 20,000 years ago. And even more striking, the first Americans didn't all come at once, but in at least three waves of migration. The fourth ancestral group had DNA tracings back to the Solutreans, people who lived in Ice Age France and Spain. Their progeny are linked by DNA to the modern day Ojibwe Indians.