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 Pakicetusbut 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, Ambulocetusmay have moved around very much like a modern sea lion. It was undoubtedly a whale that linked life on land with life at sea.
10. Which of the sentences below best expresses the essential information in the highlighted sentence in the passage?
Incorrectchoices change the meaning in important ways or leave out essential information.
o The backbone of Ambulocetus,which allowed it to swim, provides evidence of its missing fluke.
o Although Ambulocetus had no fluke, its backbone structure shows that it swam like modern whales.
o By moving the rear parts of their bodies up and down, modern whales swim in a different way from the way Ambulocetusswam.
swam like modern whales by moving the rear portion of its body up and down, even though a fluke was missing. 和选项3最为接近。