What was the Roman military like, including strengths and weaknesses?

What was the Carthaginian army like, including strengths and weaknesses?

Why were the Romans at a disadvantage at the battle of Cannae?

What happened to the survivors of the battle of Cannae?

How were elephants used in battle and what were the pros and cons of using them?

Why was Scipio important for the Romans?

How did the Romans get their revenge on Carthage and how long did it take to take?