Answer: 2) Nomadic lifestyle of Native American plains dwellers
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Answer number 2 is the only one that is most likely due to climate variations. Climate variation did not cause the discover of gold. Growth of Puritan religious influences was not caused by climate, but more of a spread of the idea throughout colonial America over time. The flow of the Mississippi south is because rivers flow downhill with gravity, and is not affected by climate.
However, the plains Indians were nomadic mainly because they follow the migration of buffalo. The buffalo migrated due to seasonal variations as they followed their food source. This makes answer 2 the best answer.
