Which statement about slavery is true

It had existed all over

the world in various forms for thousands of years

Explanation:

answer; ///i believe its (b); ///the president will sign it or veto the check first good luck

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).