题干

为研究根背光生长与生长素的关系,将水稻幼苗分别培养在含不同浓度生长素或适宜浓度NPA(生长素运输抑制剂)的溶液中,用水平单侧光照射根部(如下图),测得根的弯曲角度及生长速率如下表:

据此实验的结果,不能得出的结论是(  )

A:根向光一侧的生长速率大于背光一侧

B:生长素对水稻根生长的作用具有两重性

C:单侧光对向光一侧生长素的合成没有影响

D:单侧光照射下根的背光生长与生长素的运输有关

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答案(点此获取答案解析)

C

同类题5

根据短文理解,从A、B、C、D四个选项中选择最佳答案填空。

    The International Climate Champions (ICC) project began in 2007. It gives young people of school age a chance to speak publicly on climate change and to call on people to take action to reduce its 1 .

    Each country involved selects three teenagers to be Climate Champions, who take part in local and international activities.Climate Champion Irene Sanna lived on the Italian island of Sardinia. Irene is interested in solar energy, and  2 believes that Sardinia should use the waves around its coast to produce electricity. 'We must make our plans to save our coast, which still has no pollution. We must protect the animals, birds and fish in danger from global warming. And we must recycle.'

    Chinese student Ding Yinghan is the Beijing Climate Champion. Ding feels it is not  3 to say that just one country - his own - is causing climate change. He says the air pollution that leads to global warming comes from many parts of the world, including poorer countries that are now growing more quickly. He believes the only way to  4 the situation getting even worse is for rich and poor countriesto work together.

    Sophia Angelis, a junior student in California, is a US Champion. She's against young people's generation lack of interest in politics and feels they need to discuss the problems that really matter to their generation. Sophia strongly believes that climate change is an important issue for her generation. For her, 5 in the way teenagers behave are an important way of influencing choices made by parents.

In 2008, the Climate Champion attended the International Conference of Environment Ministers in the Japanese city of Kobe.  6 , 30 countries are involved in the ICC, and more countries are expected to join soon.