Answer:
Rome fell because it was ultimately a Stratocracy, the reason Rome expanded so easily when it was smaller was because it was more profitable to expand outside and take resources, but when the cost of garissoning, defending, and harvesting that land outweighs the benefits, holding onto that land became unprofitable, and just giving it up would seem outrageous.
The power in Rome was more focused to the Consul, or Imperator
Rome was fighting in the east, the Sassanid Persians, In the North, Germanic tribes and visigoths, and in the Northeast, the Huns.
Step-by-step explanation: