The period between 1865 and 1898 saw major transformations in U.S. immigration, driven by factors such as industrialization, urbanization, and global events. A significant segment of the immigrant population came from specific regions, leading to both cultural diversity and societal tensions. This era marked crucial changes in immigration laws and attitudes, culminating in the establishment of processes that would shape American immigration for decades to come.
Which of the following statements accurately reflects the primary source of immigration to the United States during this period?