Which option explains why the bill of rights was added to the u. s constitution

To guarantee certain rights to American citizens APEX

answer; /// i believe that the correct answer is (d)the huang he river valley;

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).