Answer:
Beringia was basically the exposed floor of the Bering Sea between and around Siberia and Alaska. The Bering Strait was part of Beringia, and it connected the two land masses of Siberia and Alaska. Historians theorize that our ancestors crossed the Bering Strait from Siberia into Alaska during the last Ice Age.
In the early 1900's, 6 million African Americans emigrated form the rural south of the US to the northeast, mid-west and west and thus began an urban existence in many of the cities in these areas so became important politically due to their numbers and their strong support of the civil rights movement later on.
Obama makes the point that America is powerful because has the potential to constantly reinvent itself. He mentions that America has enough productivity, innovation and capacity to do so. It is also a land which protects the interests of everyone and not narrow interests anymore, and this is path that had to be followed from that moment on.
agricultural economies, ie the ussr, transitioned into full on industrialieconomies through 5 year plans, started with lenin, increasing output of raw materiels like steel and coal.
