What was an important architectural feature of the city of Tenochtitlan? The canals and waterways that were built as a result of the city being built in the
middle of a lake.
The earthen mounds constructed in order to built the temples and housing of the
upper classes.
The estate built atop the hills as a retreat for the wealthy elites of society.

the canals and waterways that were built as a result of the city being built in the middle of a lake

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).