1. One way that Native Americans influenced early American colonies was by - A. building skills
B. navigational skills
C. writing down laws
D. teaching farming skills

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).

i see, would you mind putting it as one?