【单选题】
Egypt Felled by Famine
Even ancientEgypt’s mighty pyramid builders were powerless in the face of the famine that helped bring down their civilization around 2180B
C、Now evidence gleaned from mud deposited by the River Nile suggests that a shift in climate thousands of kilometers to the south was ultimately to blame and the same or worse could happen today.
The ancientEgyptians depended on the Nile’s annual floods to irrigate their crops.But any change in climate that pushed theAfrican monsoons southwards out ofEthiopia would have diminished these floods.
Dwindling rains in theEthiopian highlands would have meant fewer plants to stablize the soil. When rain did fall it would have washed large amounts of soil into theBlue Nile and intoEgypt, along with sediment from the White Nile.
TheBlue Nile mud has a different isotope signature from that of the White Nile. So by analyzing isotope differences in mud deposited in the NileDelta, Michael Krom of Leeds University worked out what proportion of sediment came from each branch of the river.
Krom reasons that during periods of drought, the amount of theBlue Nile mud in the river would be relatively high. He found that one of these periods, from 4,500 to 4,200 years ago, immediately predates the fall of theEgypt’s Old Kingdom.
The weakened waters would have been catastrophic for theEgyptians. "Changes that affect food supply don’t have to be very large to have a ripple effect in societies," saysBill Ryan of the LamontDobertyEarth Observatory in New York.
"Similar events today could be even more devastating," says team memberDaniel Stanley, a geoarchaeologist from the Smithsonian Institution in Washington,D、
C、"Anything humans do to shift the climate belts would have an even worse effect along the Nile system today because the populations have increased dramatically. \
Which of the following statements is trueA．The White Nile is the trunk of the River Nile.
B．The White Nile is the trunk of theBlue Nile.
C、The White Nile is a branch of theBlue Nile.
D．The White Nile and theBlue Nile are branches of the River Nil
网考网参考答案：D
网考网解析：
D说的是：青尼罗河和白尼罗河是尼罗河的支流。第四段中的最后一句话是这么说的：…worked out what proportion of sediment came from each branch of the river这里的“河”是指“尼罗河”，“每条支流”是指上文所说的“青尼罗河”和“白尼罗河”。因此，D是正确的答案。A：白尼罗河是尼罗河的干流。B：白尼罗河是青尼罗河的干流。C：白尼罗河是青尼罗河的支流。显然，这些都不是答案。 document.getElementById("warp").style.display="none"; document.getElementById("content").style.display="block"; 查看试题解析出处>>
Even ancientEgypt’s mighty pyramid builders were powerless in the face of the famine that helped bring down their civilization around 2180B
C、Now evidence gleaned from mud deposited by the River Nile suggests that a shift in climate thousands of kilometers to the south was ultimately to blame and the same or worse could happen today.
The ancientEgyptians depended on the Nile’s annual floods to irrigate their crops.But any change in climate that pushed theAfrican monsoons southwards out ofEthiopia would have diminished these floods.
Dwindling rains in theEthiopian highlands would have meant fewer plants to stablize the soil. When rain did fall it would have washed large amounts of soil into theBlue Nile and intoEgypt, along with sediment from the White Nile.
TheBlue Nile mud has a different isotope signature from that of the White Nile. So by analyzing isotope differences in mud deposited in the NileDelta, Michael Krom of Leeds University worked out what proportion of sediment came from each branch of the river.
Krom reasons that during periods of drought, the amount of theBlue Nile mud in the river would be relatively high. He found that one of these periods, from 4,500 to 4,200 years ago, immediately predates the fall of theEgypt’s Old Kingdom.
The weakened waters would have been catastrophic for theEgyptians. "Changes that affect food supply don’t have to be very large to have a ripple effect in societies," saysBill Ryan of the LamontDobertyEarth Observatory in New York.
"Similar events today could be even more devastating," says team memberDaniel Stanley, a geoarchaeologist from the Smithsonian Institution in Washington,D、
C、"Anything humans do to shift the climate belts would have an even worse effect along the Nile system today because the populations have increased dramatically. \
Which of the following statements is trueA．The White Nile is the trunk of the River Nile.
B．The White Nile is the trunk of theBlue Nile.
C、The White Nile is a branch of theBlue Nile.
D．The White Nile and theBlue Nile are branches of the River Nil
网考网参考答案：D
网考网解析：
D说的是：青尼罗河和白尼罗河是尼罗河的支流。第四段中的最后一句话是这么说的：…worked out what proportion of sediment came from each branch of the river这里的“河”是指“尼罗河”，“每条支流”是指上文所说的“青尼罗河”和“白尼罗河”。因此，D是正确的答案。A：白尼罗河是尼罗河的干流。B：白尼罗河是青尼罗河的干流。C：白尼罗河是青尼罗河的支流。显然，这些都不是答案。 document.getElementById("warp").style.display="none"; document.getElementById("content").style.display="block"; 查看试题解析出处>>
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