What led to the fall of the Byzantine Empire?

What led to the creation of suburbs in the early 1900s

Which of the following is an example of one of the successes of the marshall plan? a. a few eastern european countries decided to turn to democracy. b. western european economies were stronger than they had been before wwii. c. borders between western and eastern european countries shifted. d. eastern european countries eventually took part in the plan. ( answer in the format above so i can understand)

Why was russia drawn into a conflict with germany after ausria-hungary declared war on serbia ?