两栖动物的生殖和幼体发育必须在______中进行，幼体要经过________发育才能上陆生活。-八年级生物

更多内容推荐

• 对于蛙、蝾螈等两栖动物的“两栖”，我们可以理解为[]A．皮肤裸露有花纹的动物B．成体既可以在水中生活，也可以在陆地上生活C．幼体在水中发育，成体营水陆两栖D．具有变态发育的动-八年级生物
• 下列行为中，不属于雄蛙为能有大量的后代并且提高后代的存活率而必须在繁殖季节进行的行为是[]A．全力鸣叫B．抱住排卵前的雌蛙C．选择水源充沛、水质良好的场所D．筑巢-八年级生物
• “黄梅时节家家雨，青草池塘处处蛙。”春末夏初，青蛙“呱、呱、呱”的叫声此起彼伏。如果寻声找去，你会发现池塘中的青蛙正在抱对。不久以后你再来，会在水中看到小蝌蚪。如果你-八年级生物
• 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
• 青蛙、蟾蜍等两栖动物一次产卵成千上万枚，而鸟类一窝卵也只有几个，这是否说明两栖类比鸟类在生殖方面占优势呢？请说明理由。-八年级生物
• 请分析回答下列有关青蛙生殖发育及结构功能的问题：（1）在宋朝诗人赵师秀的“黄梅时节家家雨，青草池塘处处蛙”诗句中，“雨”和“蛙”的内在联系有：青蛙的受精方式为___________，发-八年级生物
• “蛙声一片”形容青蛙鸣叫响亮，那么，鸣叫的青蛙是[]A．雌蛙B．雄蛙C．雌雄蛙D．无法判断-八年级生物
• 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
• 下表是某生物兴趣小组人工孵化蛙卵的实验记录：(1)乙组孵化率低的原因有两个：一是自来水中有氯气等物质对蛙的胚胎有__________作用，二是________低。(2)采取哪些措施可提高乙-八年级生物
• _______every member has arrived, let’s set about _____ the plan for the next five years.A．Since; to
• She had no sooner finished her task ________ it began to rain.A．whenB．thanC．thatD．as soon as-英语
• The young couple, who returned my lost wallet, left _______ I could ask for their names.A．whileB．bef
• ____ regular exercise is very important, it’s never a good idea to exercise too close to bedtime.A．I
• (2014·东北三校模拟)We had just covered half the journey________the engine failed and we could do nothing b
• ________ you are supposed to do ________ you don't like a thing is change it. Don't compl
• On Christmas Eve, children are eager to know _______Father Christmas comes and puts presents into th
• There is still a lot for Chinese Women’s volleyball team to improve _____ they have obtained a stri
• Compare some recent work with your old stuff ______ you’ll see how much you’ve improved.A．butB．orC．s
• ___ I saw her, she was working in a shop.A．The last timeB．For the last time.C．To the last time.D．In
• Bring the flowers into a warm room ________ they’ll soon open.A．orB．andC．butD．for-高三英语
• He is so busy.He cannot afford enough time with his son________he wants to.(2013·四川，7)A．even ifB．as
• The new system needs to be in operation for five months ________ it can be updated.A．asB．whileC．bef
• —Don't you think it too expensive?—Never mind ________ the price is; if it is what we need we&#
• China's reform and opening has been going on for ________ is like about 30 years now and it�
• The memory is still fresh in my mind _____ I was considered the apple of my former boyfriend’s eyes
• _____ makes the school famous is _____ more than 90% of the students have been admitted to universit
• (2013·江西南昌一模)It hasn't been made clear ________ the new underground line is to be open to traff
• I'm sorry you've been waiting so long，but it'll still be some time ________ Brian get
• (2013·重庆，23)It's not easy to change habits，________ with awareness and self－control，it is possi
• Chinese actor Liao Fan won the Silver Bear for Best Actor at the 64th Berlin International Film Fest
• (2013·北京朝阳模拟)Jim came back early last night. It was not yet eight o'clock ________ he got home.
• ______ children believe they can succeed, they will never become totally confident．A．IfB．SinceC．Once
• (2013·兰州模拟)Living in the eastern part of the city has its problems, shopping is not the least. A．wi
• The spring outing really relaxed us a lot. That is its value lies.Awhat BwhereChow Dwhy-高三英语
• It is a difficult problem for high school studentsthey can properly use the Internet．A．whatB．whereC．
• A small car is big enough for a family of three ________ you need more space for baggage.A．onceB．bec
• I’m terribly sorry to have kept you waiting so long, but it’ll still be some time _________ Tony ge
• He was about to tell me the secret ______ someone patted him on the shoulder.A．asB．untilC．whenD．whi
• It was quite a long time ______ I figured out what had happened to the manager.A．afterB．beforeC．whe
• ____ you call me to say you are not coming, I will see you at the theatre at five this afternoon．A．T
• Bob is determined to get a seat for the concert _______ it means standing in line all night for the
• __ __Joe saw the film ‘ET’ directed by Steven Spielberg ,he made up his mind to turn ____ director
• ______ life pace continues to speed up, we seem to be losing the art of enjoyment.A．With B．WhenC．Whi