How did the Romans lead to the breakdown of social classes?

a result is the answer

nothing certain is known about what happened, but it seems that the country declined gradually, perhaps due to bad government, or, more likely, due to a series of bad harvests, which resulted in widespread and recurrent famine.

what are two things that greatly the american economy after the war? the huge buildup of u.s. military the beginning of the korean conflict the creation of the gi bill the marshall plan for nations