What best explains why constantinople did not fall until 1453

The city was well protected and repelled attacks by invaders.

after the roman empire, the catholic church began to unify by taking on many duties of a government.

d) a week

because the land run of 1889, although not without precedent in the history of the west, further, their men were aboard the first trains, ready to jump off and begin staking their claims. oklahoma city, edmond, and guthrie were all so affected.