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Unformatted text preview: hat features a foot with three tiny toes. Such legs would have been far too small to have supported the 50footlong Basilosaurus on land. Basilosaurus was undoubtedly a fully marine whale with possibly nonfunctional, or vestigial, hind legs.
6. The word exposed in the passage is closest in meaning to ○Explained
7. The hind leg of Basilosaurus was a significant find because it showed that Basilosaurus ○Lived later than Ambulocetus natans
○Lived at the same time as Pakicetus
○Was able to swim well
○Could not have walked on land
8. It can be inferred that Basilosaurus bred and gave birth in which of the following locations ○On land
○Both on land and at sea
○In shallow water
○In a marine environment
Paragraph 5: An even more exciting find was reported in 1994, also from Pakistan. The now extinct whale Ambulocetus natans ("the walking whale that swam") lived in the Tethys Sea 49 million years ago. It lived around 3 million years after Pakicetus but 9 million before Basilosaurus. The fossil luckily includes a good portion of the hind legs. The legs were strong and ended in long feet very much like those of a modern pinniped. The legs were certainly functional both on land and at sea. The whale retained a tail and lacked a fluke, the major means of locomotion in modern cetaceans. The structure of the backbone shows, however, that Ambulocetus swam like modern whales by moving the rear portion of its body up and down, even though a fluke was missing. The large hind legs were used for propulsion in water. On land, where it probably bred and gave birth, Ambulocetus may have moved around very much like a modern sea lion. It was undoubtedly a whale that linked life on land with life at sea
9. Why does the author use the word luckily in mentioning that the Ambulocetus natans fossil included hind legs? ○Fossil legs of early whales are a rare find.
○The legs provided important information about the evolution of cetaceans.
○The discovery allowed scientists to reconstruct a complete skeleton of the whale.
○Until that time, only the front legs of early whales had been discovered. 10. Which of the sentences below best expresses the essential information in the highlighted sentence in the passage?
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Incorrect choices change the meaning in important ways or leave out essential information. ○Even though Ambulocetus swam by moving its body up and down, it did not have a backbone.
○The backbone of Ambulocetus, which allowed it to swim, provides evidence of its missing fluke.
○Although Ambulocetus had no fluke, its backbone structure shows that it swam like modern whales.
○By moving the rear parts of their bodies up and down, modern whales swim in a different way from the way Ambulocetus swam.
11. The word propulsion in the passage is closest in meaning to ○Staying afloat
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This note was uploaded on 09/17/2013 for the course LANGUAGE 13DL208 taught by Professor Wang during the Fall '13 term at East China Normal University.
- Fall '13