How did the fall of Rome happen?

Invasions by Barbarian tribes

Explanation:

Barbarian Tribes was the cause of the fall of Rome, Rome had tangled with Germanic tribes for centuries, but by the 300s “barbarian” groups like the Goths had encroached beyond the Empire's borders.

answer; i believe the correct answer is (crops);

the answer is: c. c.it limited the president’s power to start wars.

the war powers resolution of 1973 requires the president to notify the congress whenever the president wanted to order a military operation to other countries within 48 hours. if after being reviewed the congress disagree with the proposal, that the president will be banned from ordering the operation.