The growth of to byzantium's downfall
a: constantinople
b: christendom
c: the islamic world
d: the mongol empire

A. The fall of the Constantinople was the capture of the capital of Byzantine Empire.
The attacker’s were we’re commanded by Sultan Mehmed ll who defeated Emperor Constantine Xl Palaiologos’s army. Taking control of of the imperial capital.

Hope this helps :)

Ataxation measure enacted to raise revenues for a standing british army in america