Ais a soldier that it hired for pay by a foreign state

What is the main idea of this excerpt? 1.1.3

Why might collective bargaining fail, causing a union to go on strike? a the union agrees with the boss about wages. b the boss compromises about work hours. c the factory goes out of business, causing the workers to lose their jobs. d the boss refuses to address dangerous working conditions in the factories.

What change took place in the african slave trade in the 1500's?