What were the characteristics of the Roman Republic and How did it change over time?

After the overthrow of the Roman Monarchy, the Roman Republic retained the institutions of the Monarchy, except for replacing the king with two annually elected consuls as the heads of the Republic. The senate, which had been an unelected advisory body for the king, became the advisory body of the consuls, situation evolved throufh time to give more right to plebeians and reorganized the popualr assemblys