Answer:
The Constitution requires all citizens to vote by law.
Explanation:
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.
The answer is either A or D
