题干

某兴趣小组将生物园里的二倍体黄瓜的雌花分四组,处理方法如下表.其中最可能获得二倍体无籽黄瓜的处理(    )

组别

处理

自然

状态

开花后,用适宜浓度的生长素处理柱头.

开花前套上纸袋,开花后,用适宜浓度的生长素处理柱头,然后再套上纸袋.

开花前套上纸袋,开花后,用适宜浓度的秋水仙素处理柱头,然后再套上袋.

注:黄瓜是雌雄异花植物

A:乙组

B:乙组和丙组

C:丙组

D:丙组和丁组

上一题 下一题 0.0难度 选择题 更新时间:2017-08-20 04:44:57

答案(点此获取答案解析)

C

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阅读理解

    Humans have been keeping animals as pets for tens of thousands of years, but Dr Jean-Loup Rault, an animal scientist at the University of Melbourne in Australia, believes new companions are coming: robot pets.

    “Technology is moving very fast,” Rault told ABC News, “The Tamagotchi in the early 1990s was really the first robotic pet, and now Sony and other big companies have improved them a lot.”

    This may not sit well with pet lovers. After all, who would choose a plastic toy over a lovely puppy? But Rault argues that the robotic kind has a lot going for it: “You don't have to feed it, you don't have to walk it, it won't make a mess in your house, and you can go on a holiday without feeling guilty.” The technology also benefits those who are allergic to pets, short on space, or fearful of real animals.

    It's not clear whether robot pets can replace real ones. But studies do suggest that we can bond with these smart machines. People give their cars names and kids give their toy animals life stories. It's the same with robots. When Sony stopped its repair service for its robot dog Aibo in March 2014, owners in Japan held funerals.

    As an animal welfare researcher, Rault is concerned about how robotic pets could affect our attitudes towards live animals. “If we become used to a robotic companion that doesn't need food, water or exercises, perhaps it will change how humans care about other living beings,” he said.

    So are dogs and cats a thing of the past, as Rault predicts? For those who grew up with living and breathing pets, the mechanical kind might not do. But for our next generation who are in constant touch with smart technology, a future in which lovely pets needn't have a heartbeat might not be a far-fetched dream.