Question

the processing centers at ellis and angel islands were gateways for millions seeking opportunity. what was a significant economic impact of this mass immigration on the u.s.? it shifted economic focus to agricultural exports, it spurred growth in manufacturing and infrastructure. it limited investment in industrial technologies. it reduced economic output due to labor surplus.

Explanation:

The mass immigration through Ellis and Angel Islands (late 19th-early 20th centuries) provided a large, low-cost labor force that fueled the expansion of U.S. factories, railroads, and other infrastructure. The other options are incorrect: the U.S. was shifting to industrialization, not agricultural exports; immigration supported industrial tech investment; and a labor surplus did not reduce output, it enabled growth.

Answer:

It spurred growth in manufacturing and infrastructure.