The answer is B. Scientists study artifacts they discover to form ideas on what life was like in the past. Sometimes there will pieces that doesn't make sense and so they study some more until it makes sense.
I believe the answer is slavery
Answer: not a or d but b or c would be the best guess
Explanation:
The industrial and economic developments of the Industrial Revolution brought significant social changes. Industrialization resulted in an increase in population and the phenomenon of urbanization, as a growing number of people moved to urban centres in search of employment.