Answer: a system of roads to connect the empire
Step-by-step explanation:
One of the ways to ensure that an empire is able to thrive is by making the empire more accessible within. This will ensure that people can move around more freely in the empire which will bring them closer together. There is also the advantage of being able to move troops quickly to quell rebellion.
The Persians, Romans and Incas realized this and constructed road networks to connect the empire thereby ensuring that they were able to maintain their large empires.