Nhận biết (M1)

For decades, paleontologists assumed that the enormous, long-necked sauropod dinosaurs must have been sluggish creatures that dragged their heavy tails along the ground. Recent analyses of fossilized trackways, however, reveal no tail-drag marks whatsoever, and biomechanical models indicate that the tail was held aloft to serve as a counterbalance. The lumbering image, it now appears, was an artifact of outdated assumptions rather than of the evidence itself.

Which choice best describes the overall structure of the text?

• A.

  It presents a long-standing assumption and then explains why newer evidence overturns it.

• B.

  It traces the gradual acceptance of a theory that was once highly controversial.

• C.

  It argues that fossilized trackways are an unreliable source of information.

• D.

  It compares two competing species of sauropod dinosaur.