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The plant evidence that is found in the dung fossils, though small, can be seen with naked
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![](https://static.youtibao.com/asksite/comm/h5/images/solist_ts.png)
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A.The animals over-fertilize the soil.
B.Dead plant roots can't hold the soil together.
C.The wrong types of plants are left standing.
D.There is a buildup of plant and animal matter.
A.environment
B.accumulation
C.existence
D.evidence
Climate Change
Scientists predict increasing droughts, floods and extreme weather and say there is growing evidence that human activities are to blame.
What Is Climate Change?
The planet's climate is constantly changing. The global average temperature is currently in the region of 15℃. Geological and other evidence suggests that, in the past, this average may have been as high as 27℃ and as low as 7℃.
But scientists are concerned that the natural fluctuation (波动) has been overtaken by a rapid human-induced warming that has serious implications for the stability of the climate on which much life on the planet depends.
What Is the "Greenhouse Effect"?
The greenhouse effect refers to the role played by gases which effectively trap energy from the Sun in the Earth's atmosphere. Without them, the planet would be too cold to sustain life as we know it.
The most important of these gases in the natural greenhouse effect is water vapor, but concentrations of that are changing little and it plays almost no role in modem human-induced greenhouse warming.
Other greenhouse gases include carbon dioxide, methane (甲烷) and nitrous (含氮的) oxide, which are released by modern industry, agriculture and the burning of fossil fuels. Their concentration in the atmosphere is increasing—the concentration of carbon dioxide has risen by more than 30% since 1800.
The majority of climate scientists accept the theory that an increase in these gases will cause a rise in the Earth's temperature.
What Is the Evidence of Warming?
Temperature records go back to the late 19th century and show that the global average temperature increased by about 0.6℃ in the 20th century.
Sea levels have risen 10~20 cm—thought to be caused mainly by the expansion of warming oceans.
Most glaciers in temperate regions of the world and along the Antarctic Peninsula are in retreat, and records show Arctic sea-ice has thinned by 40% in recent decades in summer and autumn.
There are anomalies (异常) however—parts of. the Antarctic appear to be getting colder, and there are discrepancies between trends in surface temperatures and those in the troposphere(对流层) (the lower portion of the atmosphere).
How Much Will Temperatures Rise?
If nothing is done to reduce emissions, current climate models predict a global temperature increase of 1.4~5.8℃ by 2100.
Even if we cut greenhouse gas emissions dramatically now, scientists say the effects would continue because parts of the climate system, particularly large bodies of water and ice, can take hundreds of years to respond to changes in temperature. It also takes greenhouse gases in the atmosphere decades to break down.
It is possible that we have already irrevocably(不可撤回地) committed the Greenland ice sheet to melting, which would cause an estimated 7m rise in sea level. There are also indications that the west Antarctic ice sheet may have begun to melt. though scientists caution further research is necessary.
How Will the Weather Change?
Globally, we can expect more extreme weather events, with heat waves becoming hotter and more frequent. Scientists predict more rainfall overall, but say the risk of thought in inland areas during hot summers will increase. More flooding is expected from storms and rising sea levels.
There are, however, likely to be very strong regional variations in these patterns, and these ere difficult to predict.
What Will the Effects Be?
The potential impact is huge, with predicted freshwater shortages, sweeping changes in food production conditions, and increases in deaths from floods, storms, heat waves and droughts. Poorer countries, which are least equipped to deal with rapid change, will suffer most.
Plant and animal extinctions are predicte
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听力原文:W: Do you know if Nick has got enough money for his study?
M: Yes. If Nick hadn't worked in the steel plant last summer, he wouldn't have earned money for his living expenses during his senior year.
Q: What does the man mean about Nick?
(13)
A.Nick can't go on studying because he has to work in a steel plant.
B.Nick has earned enough money for, his senior year.
C.Nick prefers working in a steel plant to studying.
D.Nick doesn't have enough money so he'll work during his senior year.
Why does the author say that the evidence just partly supports the theory?
A.Because what the theory suggests is only plotted by economists.
B.Because the negative relationship since 1980s is against the theory.
C.Because baby-boomers concerned the relationship is the other way around.
D.Because what the theory suggests may be a coincidence.
According to Ann Clarke, the New Zealand Life Sciences Network______.
A.should gather evidence to discredit Ingham's claims
B.should require that the research by their biologists be regulated
C.shouldn't demand that Ingham be disciplined for voicing her views
D.shouldn't appease the opposition in such a quiet way
In this passage the author argues that ________.
A) more and more evidence shows college education may not be the best thing for high school graduates
B) college education is not enough if one wants to be successful
C) college education benefits only the intelligent, ambitious, and quick-learning people
D) intelligent people may learn quicker if they don’t go to college
According to Ann Clarke, the New Zealand Life Sciences Network ______.
A.should gather evidence to discredit Ingham's claims
B.should require that the research by their biologists be regulated
C.shouldn't demand that Ingham be disciplined for voicing her views
D.shouldn't appease the opposition in such a quiet way
Foods That Fight Disease
With remarkable consistency, recent research has found that a diet high in plant -based foods—fruits, vegetables, dried peas and beans, grains, and starchy staples such as potatoes — is the body's best weapon in thwarting many health - related problems. These foods work against so many diseases that the same healthy ingredients you might use to protect your heart or ward off cancer will also benefit your intestinal tract and bones.
Here's what is currently known about these different disease -fighting foods. Cancer Fighters
Preventing cancer is a compelling reason to load up your cart in the produce department. Scientists have recently estimated that approximately 30 to 40 percent of all cancers could be averted if people ate more fruits, vegetables, and plant - based foods and minimized high -fat, high -calorie edibles that have scant nutritional value. Up to 70 percent of cancers might be eliminated if people also stopped smoking, exercised regularly, and controlled their weight.
In the past, researchers had linked fat consumption with the development of cancers, but they currently believe that eating fruits, vegetables, and grains may be more important in preventing the disease than not eating fat. "The evidence about a high- fat diet and cancer seemed a lot stronger several years ago than it does now," says Melanie Polk, a registered dietitian and director of nutrition education at the American Institute for Cancer Research.
Although scientists are still not certain about the specifics, they're beginning to close in on the healthful constituents of plant- based foods. In particular, they're looking closely at two components antioxidants and phytochemicals.
Antioxidants. The antioxidants (carotenoids, such as beta carotene and lycopene, and vitamins C and E) found in fruits, vegetables, and other plant -based foods fight free radicals, which are compounds in the body that attack and destroy cell membranes. The uncontrolled activity of free radicals is believed to cause many cancers.
The carotenoids, in particular, which give fruits and vegetables their bright yellow, orange, and red colors, are now gaining recognition for their nutritional worth. Numerous studies have extolled the virtues of lycopene (the carotenoid that makes tomatoes red) in preventing prostate cancer. One such study at Harvard University found that men who include tomato products in their meals twice a week could reduce their risk of developing prostate cancer by one third compared with men who never touch tomatoes.
Other lycopene - rich foods, such as watermelon, red grapefruit, and guava, are now piquing the interest of researchers. Watermelon not only yields more lycopene per serving (15 mg in 11/2 cups) than raw tomatoes (11 mg per 11/2 cups), but it's also a rich source of vitamins A and C.
Can watermelon help reduce the incidence of cancer? No one knows for sure because there haven' t been sufficient studies. "We assume that we'll see benefits," says Penelope Perkins Veazie, Ph. D., a research scientist with the USDA's Agricultural Research Service. Researchers there plan to compare people who eat watermelon with those who eat processed tomatoes because cooking enhances lycopene absorption—o see which group absorbs more lycopene. (A 11/2 cup serving of tomato sauce packs 53 mg of lycopene. )
Phytochemicals. The phytochemicals present in fruits and vegetables protect the body by stunting the growth of malignant cells. Phytochemicals, naturally occurring substances, include indoles ([生化]吲哚) in cabbage or cauliflower, saponins ([生化]皂角苷 ) in peas and beans, and isoflavones (异黄酮) in soy milk and tofu. Investigators have only an inkling of how many phytochemicals exist and how they work. They are confident, however, that you can get a basketful of anti- cancer nutrients by mi
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According to Ann Clarke,the New Zealand Life Sciences Network ().
A.should gather evidence to discredit Ingham’s claims
B.should require that the research by their biologists be regulated
C.shouldn’t demand that Ingham be disciplined for voicing her views
D.shouldn’t appease the opposition in such a quiet way