Question

Which led most directly to the Roman Republic's demise and its transition to an empire?

the growing divide between the rich and the poor
the failure of direct democracy
consuls staying in power too long
war with the Etruscans

Answer 1

It was primarily "the growing divide between the rich and the poor," that led most directly to the Roman Republic's demise and its transition to an empire, since this caused a great deal of social unrest.