These are my books. Where are ________?
A. their
B. your
C. theirs
D. mine
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Don't you let ____ help you ?
A. I and my friend
B. my friend and I
C. my friend and me
D. my friend and I to
利用中断杂交技术作连锁图,已知A、B、C基因转入受体菌的时间分别为6分钟、11分钟和5分钟,请问在Hfr菌株中这三个基因的顺序如何?
A. Origin-A-B-C
B. Origin-C-A-B
C. Origin-C-B-A
D. Origin-A-C-B
和F-菌株杂交最容易产生重组子的菌株类型是()?
A. F+菌株
B. Hfr菌株
C. F-菌株
D. F’菌株
以噬菌体为媒介,将细菌的小片段染色体或基因从一个细菌转移到另一个细菌的过程称之为()?
A. 转导
B. 转化
C. 性导
D. 接合