问题
选择题
某种哺乳动物的直毛(B)对卷毛(b)为显性,黑色(C)对白色(c)为显性。(这两对基因分别位于不同对的同源染色体上)。基因型为BbCc的个体与“个体X”交配。子代表现型有:直毛黑色、直毛白色、卷毛黑色和卷毛白色,它们之间的比为3:3:1:1。“个体X”的基因型为[ ]
A.BbCc
B.bbCc
C.Bbcc
D.bbcc
答案
答案:B
某种哺乳动物的直毛(B)对卷毛(b)为显性,黑色(C)对白色(c)为显性。(这两对基因分别位于不同对的同源染色体上)。基因型为BbCc的个体与“个体X”交配。子代表现型有:直毛黑色、直毛白色、卷毛黑色和卷毛白色,它们之间的比为3:3:1:1。“个体X”的基因型为[ ]
A.BbCc
B.bbCc
C.Bbcc
D.bbcc
答案:B
从A-G 选项中选出能填入空白处的最佳选项,补全对话。(选项中有两项是多余的) | |
B: Hi, Tom! A: 1 B: It's fiom Karen. She moved to New York City last year. A: New York is a good place to live in. 2 B: That's right. She said she liked the.city very much. 3 A: Sounds wonderful! B: She invited me to go to New York in the letter. A: 4 B: I think so. Well, where are you going on holiday? A: 5 I can see the beautiful ice and snow there. B: Have a good trip! A: Thank you. | |
1. _____ 2. _____ 3. _____ 4. _____ 5. _____ |