Which of the following is a country of northern europe?
a. sweden
b. germany
c. the netherlands
d. luxembourg

which time period is this? or is this story fictional, i'm going to need more info to answer this question

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).