<span>The United States experienced major waves of immigration during the colonial era, the first part of the 19th century and from the 1880s to 1920. Many immigrants came to America seeking greater economic opportunity, while some, such as the Pilgrims in the early 1600s, arrived in search of religious freedom.
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The answer should be evolutionary theory, good luck!
B. End of raids by American Indians
Answer:
It ended the labor shortage, as war veterans went to work on the railroad.
Explanation:
Positive: discovered best eastward/westward sea passages between Europe and America
Negative: revolutionized race relations
