As a result of the system of mass production, the majority of factory owners replaced skilled workers with unskilled workers.
eliminated women workers and hired only male workers.
used only child laborers.
replaced unskilled workers with skilled workers.

the correct answer is “opportunity cost”. opportunity cost is what a company misses out because it decided in one option over another one. in this case, the company decided to invest in building a factory so it gave up another possible benefit or profit in order to achieve success with the factory.  

trade-off is not the correct answer since it is a situation in which you accept losing something in return for benefits in other areas.

and finally, consequence is a general term used to accept what it comes when you make a decision. it can be a positive or negative consequence depending if the decision you took was the correct one.  

b) new machinery hope i

according to my research (britannica and quizlet) the first settlements were along the huang river because it could give the crops more fertile soil that really it out. this was due to the yellow slit caused by floods of the river.