问题 单项选择题

红绿色盲是一种常见的遗传性疾病。在生活中可以发现,男性患者的人数远远多于女性患者。出现这种现象的原因是( )。

A.控制红绿色盲的基因位于X染色体上,如果一条X染色体上携带致病基因,而另一条染色体相应位置上携带正常基因,个体并不会发病。而Y染色体上没有相应的基因
B.控制红绿色盲的基因位于Y染色体上,随Y染色体进行传递
C.控制红绿色盲的基因位于X染色体上,由于男性缺乏一种女性独有的激素,在发育过程中容易受到多种诱因的影响而发病
D.男女两性的实际患病率是相同的,只是由于两性在日常生活中偏重的领域有所不同,男性患者容易被辨认而女性患者不易被辨认

答案

参考答案:A

解析: 此题考查的是生物学常识,控制性别的染色体中XX结合是女性,XY结合为男性,女性必须要两条X染色体都带致病基因才会是红绿色盲,而男性只有一条X染色体,只要携带致病基因,就会是红绿色盲,所以红绿色盲男性比女性多。

单项选择题
句型转换

按要求改写下列句子。

1. Being a volunteer is great.(改为反意疑问句)

    Being a volunteer is great,________  ________?

2. You finish your homework. I will go to the park with you.(改为复合句)

                                                                

3."I'm listening to music," she said.(改为间接引语)

                                                                

4. Both of the boys are good at playing soccer.(改为否定句)

    ________of the boys ________good at playing soccer

5. Jim has been collecting shells for five years.(对画线部分提问)

                                                                    

6. We shouldn't talk loudly in the theater.

    We shouldn't smoke there, either,(改为同义句)

    We should________talk loudly________smoke in the theater.

7. It took them half a year to finish the work.(改为同义句)

    They________half a year in________the work.

8. I would like to go to the park tomorrow.(改为同义句)

    I ________ ________going to the park tomorrow.

9. He gets on well with his classmates.(对画线部分提问)

                                                                    

10. John's grandfather died ten years ago.(改为同义句)

      John's grandfather has________ ________for ten years.