I believe 3 is the answer, because I think the U.S bought a part of Mexico.
Explanation:
what= the immigration act of 1924 limited the number of immigrants allowed entry into the United states through a national origins quota. the quota provided immigration visas to two percent of the total of people of each nationality in the United states as of 1890 census.
why=in the 1920s ,restrictions on immigration increased. the immigration act of 1924 was most severe:it limited the overall number of immigrants and established quotas based on nationality.Among other things, the act sharply reduces immigrants from eastern Europe and Africa.
when=congress passed on emergency quota act in 1921 followed by the immigration act in 1924.
where=approximately half of immigrants living in the united states are from mexico and other latin american countries.
who=immigration to the United states in the late 1800s , between 1870s and 1900, the largest number of immigrants continued to come from northern and western Europe including great britain,scandanavia and ireland. but 'new' immigrants from southern and eastern europe were becoming one of the most important forces in american life.
