题干

已知水稻的高杆(T)对矮杆(t)为显性,抗病(R)对感病(r)为显性,这两对基因独立遗传,现将一株表现型为高杆、抗病的植株的花粉授给另一株表现型相同的植株,所得后代表现型是高杆:矮杆=3:1,抗病:感病=3:1,根据以上实验结果,下列叙述错误的是

A:以上后代群体的表现型有4种

B:以上后代群体的基因型有9种

C:以上两株亲本可以分别通过不同杂交组合获得

D:以上两株表现型相同的亲本,基因型不相同

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D

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    When other nine-year-old kids were playing games, she was working at a petrol station. When other teens were studying or going out, she struggled to find a place to sleep on the street. But she overcame these terrible setbacks to win a highly competitive scholarship and gain entry to Harvard University. And her amazing story has inspired a movie, "Homeless to Harvard: The Liz Murray Story" shown in late April.

    Liz Murray, a 22.year-old American girl, has been writing a real-life story of willpower and determination. Liz grew up in the shadow of two drug-addicted parents. There was never enough food or warm clothes in the house. Liz was the only member of the family who had a job. Her mother had AIDS and died when Liz was just l5 years old. The effect of that LOSS became a turning point in her life. Connecting the environment in which she had grown up with how her mother had died,she decided to do something about it.

    Liz went back to school. She threw herself into her studies, never telling her teachers that she was homeless. At night, she lived on the streets. ".What drove me to live on had something to do with understanding, by understanding that there was a whole other way of being. I had only experienced a small part of the society,'' she wrote in her book Breaking Night.

    She admitted that she used envy to drive herself on. She used the benefits that come easily to others, such as a safe living environment, to encourage herself that "next to nothing could hold me down".

    She finished high school in just two years and won a full scholarship to study at Harvard University. But Liz decided to leave her top university a couple of months earlier this year in order to take care of her father, who has also developed AIDS."I love my parents so much. They are drug addicts. But I never forget that they love me all the time."

    Liz wants moviegoers to come away with the idea that changing your life is "as simple as making a decision".