How has immigration changed since the 1960s?
immigration was high in the 1960s, and has gradually decreased.
immigration was low in the 1960s, increased until 2000, and then decreased.
immigration was high in the 1960s, decreased until 2000, and then increased.
immigration was low in the 1960s, and has gradually increased.

The correct answer to this question is D) Immigration was low in the 1960s, and has gradually increased.

Immigration has changed since the 1960s because immigration was low in the 1960s, and has gradually increased.

In the 1960s, immigration was based on the quota system that existed since the 1920s. The system assigned each nationality a number based on its representation in previous U.S. census. But movements such as the civil rights demanded equal treatment regardless of nationality. Nationalities like the Greeks, Italians, and Portuguese considered that the quota discriminated them.

The solution was the Immigration and Naturalization Act of 1965 or the Hart-Celler Act, that eliminated the quota system and established a new immigration policy that increased the number of immigrants that enter the country.