Final answer:
Since the 1970s, the majority of immigrants to the U.S. have come from Mexico and Central America due to economic and social factors, with a significant portion also coming from Asia, marking a shift from earlier European-dominated immigration (D).
Step-by-step explanation:
The majority of immigrants to the United States since the 1970s have come predominantly from the rest of the Americas, and specifically, a significant portion has come from Mexico and Central America. This shift marks a contrast to the earlier waves of immigration which were mainly from Europe. By the end of the twentieth century, European immigrants constituted less than 20% of the total immigrant population, whereas about half of U.S. immigration came from the rest of the Americas. Additionally, about a quarter of immigrants arrived from various Asian countries. These immigration trends are influenced by factors such as the search for better economic opportunities, escaping political turmoil, and social factors.
The majority of immigrants to the United States since the 1970s come from Mexico and Central America, driven by economic and social factors. This region has seen a significant increase in immigration due to factors such as poverty, violence, and lack of economic opportunities. Immigrants from Asia, particularly countries such as China, India, and the Philippines, also make up a substantial portion of the immigrant population in the United States.