The use of slaves was reduced, because immigrants could fulfill the same roles as slaves in factories.
Answer:
Thanks but the answer is true...
After the unification of China in the beginning of the Qin Dynasty, China's First Emperor, Qin Shihuang, linked the walls of the three northern states (Qin, Zhao, and Yan).
The correct answer is to nullify the Black Codes.
Samuel Gompers began the federation of labor.