Final answer:
Rome's legal system contributed to its expansion by maintaining order, resolving disputes, and gaining loyal allies through citizenship and alliances.
Step-by-step explanation:
The legal system in ancient Rome played a significant role in its expansion. The Romans established a system of private and public law, which helped maintain order and resolve disputes between individuals and the government. This legal system provided a sense of stability, allowing Rome to govern its conquered territories effectively. Additionally, by offering citizenship to defeated cities and forming alliances, Rome gained loyal allies and could expand its military might, further contributing to its expansion.