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B An extinct mountain goat that was once common in the Pyrenees became the first animal to be brough...
题目内容:
B
An extinct mountain goat that was once common in the Pyrenees became the first animal to be brought back from extinction.Researchers used frozen DNA to produce a clone,but the newborn kid died within minutes of birth due to breathing difficulties.
The Pyrenean ibex is a type of mountain goat,which is believed to have died out completely in 2000.Before the death of the last known individual (a 13yearold female known as Celia),biologists took cells from her skin and ears,which were frozen in liquid nitrogen (氮).An earlier cloning attempt to use the skin cells failed.But the latest attempt involved the creation of 439 cloned embryos (胚胎).Of these cloned embryos,57 were put into the female domestic goats,but only one goat gave birth and the newborn cloned kid died after seven minutes as a result of lung disease.
Researchers say that other cloned animals,including sheep,have been born with similar lung disease,but they say that overall the experiment was a major step forward in the effort to bring the ibex back to its mountain home.The leading researcher Jose Folch says,“The cloned kid was genetically like the ibex.In species such as the ibex,cloning is the only possibility to avoid its complete disappearance.”
The failure to produce a living clone from DNA that was frozen only fifteen years ago shows the difficulty researchers would face in trying to bring back species that have been extinct for decades or centuries. Researchers have had the idea of bringing back the Tasmanian tiger, which went extinct in 1936. There are,however, other species that have been seriously suggested for cloning, such as the giant panda, the African bongo antelope, the Sumatran tiger and the pygmy hippo. Supporters believe cloning provides hope of keeping these endangered animals alive before they die out.
1.What do we know about the cloned ibex?
A. It died of lung disease.
B. It was the first cloned animal in the world.
C. It lived for thirteen years.
D. It was born in 2000.
2.We can conclude from the passage that ________.
A. cloning has developed quickly in developed countries
B. no more animals will die out in the future
C. cloning makes it possible to preserve endangered species
D. cloning seldom results in physical problems for animals
3.What’s the best title for this passage?
A. Great advancement in cloning goats
B. Difficulties in saving extinct animals
C. Public concerns about cloning
D. Cloning brought back an extinct species for a while
4.In which part of a newspaper would you most probably read this passage?
A. Society. B. Sports.
C. Amusement. D. Science.
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