Pls help What was the Columbian Exchange and how did it affect Native Americans and Europeans?

How did the american revolutionary war change how some americans viewed the enslavement of african americans?

In what year did vladimir lenin and the bolsheviks seize power in russia? 1885 1900 1917 1961

Plz which of the following countries did not claim the oregon country in the early 1800s. a. russia. b. britain. c. the united states d. france.