Considering the resources available to the union why was the union unable to defeat the confederacy quickly?

The most convincing 'internal' factor behind southern defeat was the very institution that prompted secession: slavery. Enslaved people fled to join the Union army, depriving the South of labour and strengthening the North by more than 100,000 soldiers. Even so, slavery was not in itself the cause of defeat.

Explanation:

the conditions that made the byzantine empire vulnerable to attacks by the muslin turks were the sack of constantinople by western crusaders, the conquests of the sultanate of rum, presence of rival kingdoms and finally the set up of fiefdoms at the empire which were owned by the ghazis (turkish warriors).

by improved communication.