Answer:
Right choice:
Africans crossed into South America when Africa and South America were one continent.
Explanation:
Such a statement is totally absurd. Humans as a species had not appeared on planet Earth when present-day Africa and South America were part of the same land mass hundreds of millions year ago. So, African could not cross to South America in the times of Pangea, the only megacontinent in the planet´s evolution. The other options are theories of the origins of man in the Americas, though there´s no consensus in the academic community.
The American Federation of Labor was national federation of labor unions in the U.S. They emerged from a dispute with the Knights of Labor organization. They organized workers in craft unions.
B. Interchangeable parts were identical parts that could be exchanged for one another in the manufacture of guns, clocks, and other goods.
