試題詳解

20. Which of the sentences below best expresses the essential information in the highlighted sentence in paragraph 5 in the passage?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.
(A)Even though Ambulocetus swam by moving its body up and down, it did not have a backbone.
(B) The backbone of Ambulocetus, which allowed it to swim, provides evidence of its missing fluke.
(C) Although Ambulocetus had no fluke, its backbone structure shows that it swam like modern whales.
(D)By moving the rear parts of their bodies up and down, modern whales swim in a different way