Câu hỏi:

Read the following passage and mark A, B, C, or D to indicate the correct answer to each of the blanks from 46 to 50.

University researchers have taken samples from a preserved dodo specimen in an (46) _____ to uncover the extinct bird‟s family tree. They worked with the British Natural History Museum to collect and study genetic material from large number of specimens: a preserved dodo, the extinct solitaire bird, and 35 kind of living pigeons and doves. Their analysis (47) _____ the doo and the solitaire to be close relatives with the Nicobar pigeon, their nearest living relative. The dodo lived on Mauritius in the Indian Ocean. It was a flightless bird, bigger than a turkey. By 1681, all dodos had been (48) _____ by hungry sailors. The solitaire, which looked a bit like a dodo, had gone the same way by 1800. By extracting short pieces of the dodo‟s DNA and (49) _____ these with the DNA of living birds, the scientists were able to deduce when the dodo evolved away from its relatives into a separate entity. The scientists can now (50) _____ assume that the dodo developed its distinctive appearance and features as a result of its geographical isolation. They are now convinced that it separated from the solitaire about 25 million years ago, long before Mauritius became an island.