题目

现有甲、乙、丙三种元素，其原子序数都不超过20。有关信息如下： 元素代号相关信息 甲n为电子层数，甲原子最外层电子数为2n2－1 乙在周期表中它的周期数为k，主族序数为2k＋1 丙电子层数大于最外层电子数 下列关于甲、乙、丙三种元素相关的分析正确的是( ) A．甲的单质难溶于水 B．乙的气态氢化物遇湿润的pH试纸变红色或蓝色 C．丙的最高价氧化物对应的水化物是易溶于水的强碱 D．甲、丙只能形成共价化合物With only about 1, 000 pandas left in the world, China is desperately trying to clone(克隆) the animal and save the endangered species. That’s a move similar to what  Texas A & M University researchers have been undertaking for the past five years in a project called “Noah’s Ark”. Noah’s Ark is aimed at collecting eggs, embryos(胚胎), semen and DNA of endangered animals and storing them in liquid nitrogen(氮). If certain species should become extinct, Dr. Duane Kraemer, a professor in Texas A & M’s College of Veterinary Medicine, says there would be enough of the basic building blocks to reintroduce the species in the future. It is estimated that as many as 2, 000 species of mammals, birds, reptiles will become extinct in over 100 years. The panda, native only to China, is in danger of becoming extinct in the next 25 years. This week, Chinese scientists said they grew an embryo by introducing cells from a dead female panda into the egg cells of a Japanese white rabbit. They are now trying to implant the embryo into a host animal. The entire procedure could take from three to five years to complete. “The nuclear transfer(核子移植) of one species to another is not easy, and the lack of available(capable of being used) panda eggs could be a major problem,” Kraemer believes. “They will probably have to do several hundred transfers to result in one pregnancy (having a baby). It takes a long time and it’s difficult, but this could be groundbreaking science if it works. They are certainly not putting any live pandas at risk, so it is worth the effort,” adds Kraemer, who is one of the leaders of the Project at Texas A& M, the first-ever attempt at cloning a dog. “They are trying to do something that’s never been done, and this is very similar to our work in Noah’s Ark. We’re both trying to save animals that face extinction. I certainly appreciate their effort and there’s a lot we can learn from what they are attempting to do. It’s a research that is very much needed.” 60. The aim of “Noah’s Ark” project is to _______.A. make efforts to clone the endangered pandas B. save endangered animals from dying outC. collect DNA of endangered animals to study D. transfer the nuclear of one animal to another61. According to Professor Kraemer, the major problem in cloning pandas would be the lack of _______.A. available panda eggs                B. host animalsC. qualified researchers                D. enough money62. The best title for the passage may be _______.A. China’s Success in Pandas Cloning                       B. The First Cloned Panda in the World C. Exploring the Possibility to Clone Pandas   D. China —the Native Place of Pandas Forever63. From the passage we know that _______.A. Kraemer and his team have succeeded in cloning a dog B. scientists try to implant a panda’s egg into a rabbit C. Kraemer will work with Chinese scientists in clone researchesD. about two thousand of species will probably die out in a century