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Nội dung: <blockquote data-quote="tuan1990" data-source="post: 92258" data-attributes="member: 77737">Many Animal Populations Facing ThreatsHướng dẫn: Nhấn nút Play để nghe, đoán từ cần điền vào chỗ trống, bôi đen chỗ trống để xem đáp án.[MP3]https://server1.vnkienthuc.com/files/3/Media/sin-2508-digest-11-04-08_0.mp3[/MP3]This is SCIENCE IN THE NEWS in VOA Special English. I'm Bob Doughty. And I'm Barbara Klein.This  week, we will tell about mammal populations in danger of disappearing.  We will also tell about one kind of animal that disappeared long ago.  And, we will examine some traditional beliefs about the viruses that  cause influenza and the common cold.(MUSIC)A [A]worldwide  study[/A] has found that almost twenty-five percent of wild mammals are in  danger of permanently disappearing. [A]Scientific researchers[/A] considered  all known mammal populations. The researchers say permanent[A] disappearance[/A]  threatens at least one thousand one hundred forty-one  species or groups of animals. Mammals are the closest relatives to human  beings.The researchers are blaming loss of habitat, or[A] living  space[/A], and hunting for threatened land mammals. They say water mammals  suffer more from pollution, being hit by ships and caught in fishing  nets.One thousand seven hundred experts worked on the study. They  are from one hundred thirty [A]countries[/A]. Their findings were reported at  the World Conservation Conference of the International Union for  Conservation of Nature in Barcelona, Spain.The report was  presented in connection with the Red List of Threatened Species. The  World Conservation Conference [A]announces[/A] the Red List each year. The list  contains almost forty five thousand animals and [A]plants[/A]. Of those,  almost seventeen thousand, or about thirty eight percent, are threatened  with extinction.Some scientists say the report provides[A] evidence[/A]  that Earth's wildlife is going through[A] widespread [/A]extinction. The last  such period may have taken place millions of years ago, when dinosaurs  became extinct.Jan Schipper led the writing of the report. He directs the I.U.C.N.'s program that observes animal [A]populations[/A] worldwide.Mr.  Schipper says up to thirty six percent of mammals could be facing  extinction. He says this is true because not much information exists  about some [A]species[/A]. At least seventy-six mammals have [A]permanently  disappeared[/A] since fifteen hundred.The director general of the  I.U.C.N., Julia Marton-Lefevre, says human activity could cause loss of  hundreds of species. She says that is a [A]frightening sign[/A] of what is  happening to habitats. Still, the report said human efforts also could  help save some species. Ms. Marton-Lefevre is calling for action to make  that happen.For study purposes, the I.U.C.N. [A]divides[/A] animals  into groups. The scientists call animals that have disappeared, or  almost disappeared, extinct or nearly extinct. A frog-like creature  called Holdridge's toad was declared extinct. It lived only in Costa  Rica.Other divisions depend on the amount of threat the [A]animals  face[/A]. The animals in most danger are considered critically endangered.For  example, the Iberian lynx is called [A]critically endangered[/A]. As few as  eighty-four adult members of the large, cat-like animals remain alive.The  Red List identifies the second most threatened animals as endangered.  The scientists named a Southeast Asian animal, the fishing cat, as among  the endangered. Part of the fishing cat's wetland habitat no longer[A] exists[/A] .(MUSIC)A new study suggests the last [A]woolly  mammoths[/A] in Siberia were native to North America. Scientists had  believed these mammoths came from Europe or Asia.The study  involved genetic evidence from the remains of the[A] ancient animal[/A]. Woolly  Mammoths share an ancestor with modern-day elephants. The mammoth is  recognizable for its long hair and large tusks.Woolly mammoths[A]  disappeared [/A]thousands of years ago, after Earth's most recent ice age.  But mammoths were able to survive for thousands of years. During this  period, they slowly changed to live in extremely cold climates.Scientists  believe the ancestors of woolly mammoths came from Africa. As the  African mammoths moved north to Eurasia, scientists believe, they grew  long hair to[A] protect [/A]them from the extreme cold of Siberia.To  better understand these animals, an international research team examined  genetic material from more than one hundred woolly mammoth remains. The  remains were found in North America, Europe and Asia. These fossils  came from woolly mammoths that lived between forty-four thousand and[A]  eleven thousand years[/A] ago.Hendrik Poinar is a molecular  evolutionary geneticist at McMaster University in Ontario, Canada. He  and his team examined genetic material from fossilized teeth and pieces  of bones from woolly mammoths. They also examined results of earlier  woolly mammoth [A]studies[/A].Until recently, many scientists believed  that mammoths came from Europe and Asia because that is where the oldest  fossils were found. Earlier studies of the mammoths[A] involved[/A] only one  continent at a time. The researchers discovered that mammals traveled  back and forth several times between Eurasia and Alaska over thousands  of years. The animals were able to travel on a land bridge that  connected Siberia and Alaska during low [A]sea levels[/A].The  researchers discovered that the mammoths were divided in three [A]major  groups[/A]. One group lived mainly in Asia. Another group lived mainly in  the Americas. And, a third group lived in both places. They believe the  American mammoths traveled back across the Bering Strait and in time  replaced the other populations of mammoths.The researchers  believe the animals moved the great distances in [A]search [/A]of food. A  report with their findings was published in Current Biology. Other  researchers [A]disputed[/A] the findings. They say the study is based on only  limited information.(MUSIC)Autumn and winter are cold and  flu season -- when people are most likely to catch the viruses that  cause [A]influenza [/A]and the common cold.Is the old advice true that  wearing warm clothing will help prevent[A] a cold[/A]? Or if you do get sick,  should you follow the old saying, "Feed a cold and starve a fever"? And  what about that fever? Should you take medication to reduce your  temperature, or is it better to let the body treat the [A]infection[/A] itself?Everyone seems to have an answer. But how much value is there in [A]popular wisdom[/A]?Doctor  Alvin Nelson El Amin knows a lot about cold and flu season. He is  medical director of the immunization program for the Los Angeles County  Department of Public Health in California.Doctor Nelson El Amin  says studies may be just starting to provide evidence for long-held  beliefs. For example, scientists for years dismissed the idea that  getting cold and wet might cause colds or flu.But recent studies  have shown that cold [A]temperatures[/A] cause stress on the body. That stress  can create conditions more inviting to viruses. So maybe it does make  sense to wrap up warmly before[A] leaving home[/A].And what about the  advice to feed a cold and starve a fever? Doctor Nelson El Amin says you  should eat if you have a cold and are hungry. But [A]a higher than normal  body temperature[/A] suggests a more serious problem. He says people are  usually not hungry anyway when they have a high fever. Eating might even  cause a person to vomit. But drinking plenty of liquids is important. A  fever can easily dehydrate the body.Finally, when should you  treat a fever? Doctor Nelson El Amin says a fever should be treated if  it stays at forty degrees centigrade or above for [A]a day or more[/A]. A  temperature that high can damage brain cells. The doctor also believes  in treating a fever if it prevents a person from sleeping.Aspirin,  acetaminophen and ibuprofen can all be used to reduce pain and fever.  But aspirin should not be given to children because it can cause a rare  condition.One belief that Doctor Nelson El Amin wanted to make  clear is wrong is that influenza vaccine can cause the flu. It cannot.  Sometimes people get the flu from [A]another person[/A] soon after they get  vaccinated, so they blame the vaccine, he says.But, [A]flu vaccines[/A]  do not protect everyone who gets them. Still, even if a person does get  sick, the vaccine can[A] limit the effects[/A] of the virus.(MUSIC)This  SCIENCE IN THE NEWS was written by Jerilyn Watson, Caty Weaver and  Brianna Blake, who also was our producer. I'm Barbara Klein. And I'm Bob  Doughty. Read and listen to our programs at voaspecialenglish.com.  Listen again next week for more news about science, in Special English,  on the Voice of America.</blockquote>

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