Based on congressional priorities with respect to immigration, one might assume that the largest numbers of recent immigrants to the united states are

Relatives to people who are already here is the answer in this question. People who are already in the country and earn much money to make their family lives immigrate to that country because their life will be stable. So the relative of the person who are already in that country is the reason why there has a large number of immigrants.

Doesn't your school check for plagarism?