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单项选择题

在冰箱还没有被发明之前，俄罗斯人必须往牛奶桶里放哪种动物来达到保鲜效果？

A.蛇
B.青蛙

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热门试题

单项选择题What is the wrong description of the evolution of bacterial resistance?

A．The human gut is considered another hotspot for such genetic exchanges between pathogens and commensals
B．The main role of integrons is gene cassette capture followed by recombination into an attachment site and gene expression via activation of the SOS system.
C．Integrons are not a major source of transferable resistance determinants, both in Gram-negative and Gram-positive bacteria
D．direct DNA acquisition from the environment is an important evolutionary mechanism exhibited by bacteria

单项选择题FC–1“枭龙战机”是我国与哪个国家联合研制的？

A.巴基斯坦
B.以色列