What role did slavery play in the southern economy during the American civil war?

The maps below show the middle east. which best explains how the green areas depicted in the image on the left are reflected in the population map on the right? populations are greater in fertile areas that are close to freshwater sources, which is why more people live near deserts. populations are greater in fertile areas that are close to freshwater sources, which is why more people live near oceans. populations are greater in fertile areas that are close to freshwater sources, which is why more people live near mountains. populations are greater in fertile areas that are close to freshwater sources, which is why more people live near rivers.