Why do you think scientists aren't sure how the first people came to the americas?

Which portuguese explorer discovered brazil

It can be inferred that the dramatic increase in defense spending by germany was the result of. (a) attempts by great britain to take german colonies. ( b) fear of a two-front war against france and russia (c) the need to put down a communist rebellion (d) a competition with the allies to produce atomic weapons

What does the second video tell you about life in the united states compared to life in russia?