The United States became a part of the world-system core
A) in the 1600s.
B) in the 1700s.
C) in the 1800s.
D) at the end of World War I.
E) at the end of World War II.
Question 2
What was the single most important innovation stimulating the international division of labor?
A) sewing machine
B) railroad
C) metal-hulled, ocean-going steamship
D) cargo truck
E) jet-engine airplane