Matura rozszerzona – czytanie, ćwiczenie 22

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The remains of a woolly mammoth recently discovered in Siberia could be the best hope yet for scientists aiming to clone the massive, long-extinct beast. In May 2013, scientists from the Siberian Northeastern Federal University reached a small island in the far north of Siberia, as there were rumours that a mammoth was lying under the ice there. 1. _____ But when the researchers dug further, they found an almost complete mammoth, with three legs, most of the body, part of the head and the trunk still intact. During the excavations, they saw dark red smudges on the animal’s skin, which they thought might be mammoth blood.

The researchers then took the body to Yakutsk in Russia, where a group of experts had only three days to thoroughly examine the specimen before it was refrozen to prevent rotting. 2. _____ Further tests conducted on the mammoth’s teeth revealed it was likely to have been in its mid-50s. While scientists were examining the elbow of the mammoth, blood samples were collected. Unlike humans and other mammals, mammoths evolved a cold-resistant form of hemoglobin, which enabled them to survive in the near-freezing temperatures during the Ice Age.

The discovery of the mammoth might be the key element enabling scientists to clone that extinct species. But whether or not Buttercup can be brought back to life is another matter. 3. _____ Previously found mammoths looked exceptionally well-preserved but have yielded only a few dried specks of blood, and none of them had enough intact DNA for a cloning experiment. So far, the team hasn’t found a complete copy of the mammoth’s genome. But Buttercup’s tissue has revealed some very long fragments of DNA that could potentially be pieced together to recreate the genome. 4. _____ For example, George Churchen from Harvard University hopes that combining DNA from Buttercup with DNA from modern-day elephants will allow for that. However, the experiments have not produced any decisive results yet.
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A. The team used carbon dating and determined that the mammoth, nicknamed Buttercup, lived about 40,000 years ago.
B. To make this bold dream a reality, a complete copy of DNA is essential.
C. Based on their condition, scientists determined that Buttercup was probably not in the best of health when she died but a more detailed genetic analysis is necessary.
D. And even if a complete sample of undamaged DNA can’t be found, there may be other ways to clone a mammoth.
E. At first, they saw only parts of two giant tusks sticking out of the ground.