Next, could we really clone extinct animals?
In theory? Yes. To do this, you need a well-kept source of DNA from the extinct animals such as wool mammoth (毛象), Tasmanian tiger, or even dinosaur, and a closely related species, still living, which could serve as a surrogate mother.
In reality? Probably not. On the one hand, it’s not likely that extinct animals’ DNA could survive undamaged for such a long time. Cloning extinct animals as wool mammoth, Tasmanian tiger, or dinosaur is much more difficult due to the lack of properly well-preserved DNA. On the other hand, for example, a gaur can have a cow as a surrogate mother, definitely not a monkey. But what about an extinct animals as unique as the panda? What species could possibly serve as a surrogate mother?
Cloning presents many exciting possibilities. However, even if extinct animals are brought back, they could not survive in today’s world. Not only do most extinct animals have no habitat to live in, but the other plants and animals they depended on for food may also be gone as well.
60. It can be learned from the text that ________.
A. scientists have cloned the African bongo antelope
B. both the cheetah and the giant panda live in Asia
C. the gaur lives in Asia and is endangered
D. the gaur is an extinct species
61. The underlined words "a surrogate mother" probably refer to a female who ______.
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