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Egypt Felled by Famine The ancient Egyptians depended on the Niles annual floods to irrigate their crops. But any change in climate that pushed the African monsoons southwards out of Ethiopia would have diminished these floods. The Blue Nile mud has a different isotope signature from that of the White Nile. So by analyzing isotope differences in mud deposited in the Nile Delta, Michael Krom of leeds University worked out what proportion of sediment came from each branch of the river. The weakened waters would have been catastrophic for the Egyptians. Changes that affect food supply dont have to be very large to have a ripple effect in societies, says Bill Ryan of the Lamont Doherty Earth Observatory in New York. 词汇： dwindle 逐渐变少，逐渐变小;使变少，使变小 geoarchaeologist 地质考古学家 signature 签名;特征 注释： 2.Ethiopia：埃塞俄比亚 4.the White Nile：白尼罗河 1. Why does the author mention pyramid builders? B. because they were well-built D. because even they were unable to rescue their civilization A. Change of climate C. food 3. Which of the following statements is true? | 
