How many weeks were kids under the age of 12 in school in the 1900s

The answer is 15 weeks.

Explanation:

They ranged from untidy to absolutley filthy, according to a study in 1917. In 1900, 78% of all children were enrolled in American Schools; By 1910 the percentage had increased only slightly to 79%. In 1905 the average school term lasted 151 days, to which the average student attended 105 days. And 105 divided by 7 is 15.

just finished this it is b. centrifugal force

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).