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    Every year animals all around the world take part in some wonderful journeys．Here are the stories of two amazing animal travelers．

    Humpback whales （ 座 头 鲸 ） prefer a slow journey．The humpbacks，

    which travel over 10，000kilometers on their journey from Alaska to Hawaii，swim at a relaxing speed of about 1.6kilometers an hour．Although they don't swim fast，humpback whales travel farther than any other kinds of whale．

    Every August a fantastic sight can be seen in the skies above Ontario and Montreal﹣millions of amazing Monarch butterflies （ 帝 王 蝶） beginning their 4，000﹣kilometer journey from Canada to Central Mexico．In fact，the journey，which takes about 3months，is longer than the average （ 平 均 的 ） life of the butterfly．Finally many of the butterflies reaching their final place are the great grandchildren or even the great great grandchildren of the butterflies who began the journey in Mexico the year before．

①有口有肛门；②身体呈两侧对称；③生殖和发育脱离了水的限制．

如图所示是探究“阻力对物体运动影响”的实验装置．下列有关此探究活动的各种表述，错误的是(    )