There were many factors that allowed the Byzantine Empire to last a 1000 years after the end of the Roman Empire which include the fact that Constantinople, the capital of the Byzantine Empire, was protected with walls that lasted almost the entire 1000 years, making Constantinople, and the center of the empire's economy/culture impervious to invaders.
Answer:
go into ur room lock the door and study
avoid using the phone
C. The process of evolution
Im not 100% about the answer, but i think its Starvation.
Without resources or wealth they couldnt obtain food.
-Seth
