The city of new orleans is in the delta of a great river. during hurricane katrina most of the city flooded but the area along the river, like the french quarter, did not. why didn't these areas flood?

the great wall of china worked as a defense for the feudal states of the zhou dynasty to the north. during the warring states period more walls were put up to defend the borders of the different kingdoms. it was semi successful because despite the wall, the mongols eventually conquered china also the great wall provided protection to the economic development and cultural progress, safeguarded the trading routes such as the silk road, and secured transmission of information and transportation. @jayxboof

c or d both can be the answer