As a result of the Industrial Revolution. A many workers were forced to live in slum conditions.
B overseas migration increased.
C workers salaries doubled.
D working conditions improved​

A.many workers were forced to live in slum conditions.

Explanation: While technology improved, many other things did not, cities grew rapidly and became severely over populated, leaving many with unfair wages, awful working conditions, and living in the slums.  

after the roman empire, the catholic church began to unify by taking on many duties of a government.

small european communities with shared traditions consolidated into large new states (apex)