ASAP What is the Prisoner's Dilemma, and how is it applicable to Economics, particularly in regard to negative externalities?

Draw conclusions  why might a cause like italian unification successfully draw people of very different backgrounds together?  

The crittenden compromise which option explains the role that this legislation played in the buildup to the civil war? it attempted to resolve the complications introduced by the missouri compromise; this to stave off the civil war. it sought to encourage southern diplomats to take their seats in congress so their voices could be heard in government. it proposed six amendments to the constitution aimed at protecting slavery; however, its passage was blocked by congress. it attempted to establish stipulations that made secession from the united states constitutionally legal.

What pact signed on 1949 reinforce that the united states would not return to an isolationist policy