Why did a series of civil wars follow the overthrow of nero?

When Nero fell out of power there was a power vacuum.  

This is true for when any power leaves an empire.  

The correct answer is b

The electoral college consists of 538 electors. a majority of 270 electoral votes is required to elect  the president. your state's entitled allotment of electors equals the number of members in its congressional delegation: one for each member in the house of representatives plus two for yoursenators.congress does the electoral college represent