题干

图表示雄果蝇体内某细胞分裂过程中,细胞内每条染色体DNA含量变化(甲曲线)及与之对应的细胞中染色体数目变化(乙曲线).下列说法不正确的是(  )

A:CD与FG对应的时间段,细胞中均含有两个染色体组

B:D点所对应时刻之后,单个细胞中可能不含Y染色体

C:EF所对应的时间段,DNA含量的变化是由于同源染色体的分离

D:BD对应的时间段,可发生姐妹染色单体相同位点上的基因变化

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答案(点此获取答案解析)

C

同类题2

        Some people think only school children do not agree with their parents, however, it is not true.   1  is a problem for parents and children of all ages. If it's hard for you to communicate with your   2 , don't worry about it. Here is some advice for you to bridge the generation gap (代沟).
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         Talk about your  14 . The values of your parents are probably different from those of your own. Tell your parents what you 15  about, and why. Understanding your values might help them see your purposes in life.
      A good relationship with your parents can make you a better and happier person. It is worth having a try!