下列水中生活的动物，属于脊椎动物的是（ ）
A．海蜇
B．章鱼
C．梭子蟹
D．鲫鱼
海蜇生活在水中，体壁由内胚层、外胚层和中胶层构成，体内有消化腔，有口无肛门，属于腔肠动物；章鱼属于软体动物；梭子蟹属于甲壳动物．它们的背部无脊椎骨组成的脊柱，属于无脊椎动物．而鲫鱼生活在水中具有鳍和鳃等特征，为鱼类，背部有脊椎骨组成的脊柱，属于脊椎动物．
故选：D
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| The largest earthquake in Japanese history 1 in northern Japan at 2:46 pm of March 11, 2011. A tsunami (海啸) followed, causing major flooding in 2 areas of Japan, as well as many strong aftershocks (余震). So far more than 13,000 people 3 with about 14,000 people missing. When news of this disaster(灾难) 4 China, many Chinese people expressed their 5 for Japan and the Japanese, remembering that Japan helped the Chinese during China's 2008 Sichuan Earthquake. | ||||
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