问题
选择题
人类卵子细胞中，染色体的组成是（ ）
A．22对常染色体和一对性染色体XY
B．22条常染色体和一条Y染色体
C．22条常染色体和一条X染色体
D．22对常染色体和一对性染色体XX
答案
人的性别遗传过程如图：
从图解中看出，人类卵子细胞中，染色体的组成是22条常染色体和一条Y染色体．
故选：B．
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人类卵子细胞中，染色体的组成是（ ）
A．22对常染色体和一对性染色体XY
B．22条常染色体和一条Y染色体
C．22条常染色体和一条X染色体
D．22对常染色体和一对性染色体XX
人的性别遗传过程如图：
从图解中看出，人类卵子细胞中，染色体的组成是22条常染色体和一条Y染色体．
故选：B．
| 根据对话内容，从方框内的选项中选出能填入空白处的最佳选项。选项中有两项为多余选项。 | |
| Tang Jun is chatting with his e-pal David (和网友大卫聊天) on QQ. (D: David; T: Tang Jun) D: Hi, how is it going these days? T: Pretty good! We celebrated our Dragon Boat Festival (端午节) last week. D: Dragon Boat Festival? 1______ T: To remember an ancient Chinese poet (诗人). D: How do you usually celebrate it? T: 2______ But this year, we did something more interesting. D: What did you do? T: Our school had a Dragon Boat race. D: 3______. Who won the race? T: Our class. D: 4______ T: Thanks a lot. I hope you can come to China sometime. D: 5______ I'm interested in Chinese traditions. Tell me more about them next time. T: OK, I will. See you. D: See you!
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