From the colonial era to today, immigration to the United States has changed and developed in distinct phases or "waves.” A. For each of the time periods below, describe the major wave of immigration to the US that occurred and identify the continents or regions sending migrants.

1609–1775
1820–1920
1950–present
B. Within the second and third waves (1820–1920 and 1950–present), smaller waves of immigration occurred as migration sharply increased from particular countries or regions.

Provide examples of at least two of these subphases for each time period. Identify the countries or regions sending migrants and give examples of the push or pull factors driving migration.

C. Changes in circumstance can greatly affect push and pull factors. Provide two examples of changes to push and pull factors that caused waves of migration to begin or end. Make a connection to historical examples for each.