The truce that was created in congress by the missouri compromise began to break down when

a)new territories were opened for expansion after the mexican-american war
b)manifest destiny forced thousands of settlers to move west.
c)the civil war erupted, dividing the nation
d)the dred scott decision was issued by the supreme court

B)Manifest Destiny forced thousands of settlers to move west.

Ifound this on google “simply, the working conditions were terrible during the industrial revolution. as factories were being built, businesses were in need of workers. with a long line of people willing to work, employers could set wages as low as they wanted because people were willing to do work as long as they got paid.” i hope this you for what your looking for.