What distinguished the third and final migration from Asia to the Americas from the previous two?

Question

Quizplus · Accepted Answer

The third and final migration from Asia to the Americas occurred long after Beringia, the land bridge that connected Asia and North America, had disappeared under the rising seas. This is what distinguishes it from the previous two migrations. The first migration occurred at least 15,000 years ago, while the second occurred around 5,000 years ago, both during the existence of Beringia.

What Distinguished the Third and Final Migration from Asia to the Americas