与蝌蚪相比，只有成蛙才具有的结构是[]A．鳃B．尾C．肺D．心脏-八年级生物

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• 鸣叫的青蛙是______性的，它的口角边有一对鸣囊。在青蛙抱对的池塘水面，会发现漂浮着的一片片胶状透明物，这是青蛙的卵块，里面有许多________。-八年级生物
• 青蛙的生殖方式是[]A．体外受精，卵生B．体外受精，变态发育C．体内受精，卵生D．体内受精，变态发育-八年级生物
• 青蛙和大豆个体发育的起点分别是[]A．受精卵、受精卵B．蝌蚪、种子C．蝌蚪、花粉粒D．受精卵、种子-八年级生物
• 将鸟受精卵的下列结构与其功能用线连接起来。①卵壳②卵壳膜A．将来发育为雏鸟③胚盘B．保护作用④卵白C．供给胚胎发育所需要的营养物质⑤卵黄-八年级生物
• 两栖动物的幼体发育成成体要经过[]A．变态发育B．不完全变态发育C．完全变态发育D．完全变态和不完全变态发育-八年级生物
• 两栖动物的生殖和幼体发育必须在______中进行，幼体到成体要经过_______发育。-八年级生物
• 对蛙的生殖发育有直接影响的是[]A．空气污染B．噪声污染C．水质污染D．固体废弃物污染-八年级生物
• 雌蛙与雄蛙之间抱对的意义是[]A．捉住雌蛙，防止雌蛙逃走B．培养感情，建立起相对稳定的配偶关系C．雌蛙与雄蛙之间的识别D．雌蛙和雄蛙同时排出生殖细胞，提高受精卵形成的机率-八年级生物
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