1958年Meselson和Stahl利用15N标记大肠杆菌DNA的实验首先证明了下

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问题:

1958年Meselson和Stahl利用15N标记大肠杆菌DNA的实验首先证明了下列哪种机制

A.DNA能被复制
B.DNA基因可转录mRNA
C.DNA基因可表达为蛋白质
D.DNA的半保留复制机制

考点:普通考研西医综合西医综合
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()强调规章至上,凡事循规蹈矩,要求员工有章可守,有法可依。企业强调组织结构的正规化,企业管理追求稳定性和持久性。

A.家族式企业文化

B.发展式企业文化

C.市场式企业文化

D.官僚式企业文化

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当电网发生故障,如有一台变压器损坏时,其他变压器允许长时间过负荷运行。

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In China, a lot of food is wasted every year and the waste food is e 小题1:  for 200,000,000 people. The food is wasted in restaurants, at home and in schools, etc.

In restaurants or at home, people often o 小题2:  or cook too much food. But they can’t eat it up . When they go out of a restaurant, f 小题3: and happy, they n小题4: look back at the uneaten food on the table again. Should Chinese consumers(消费者) feel sorry for the terrible w 小题5:  ?

In schools, we can often see a lot of students throw food away after m 小题6: and they only eat the food they like.

Everyone is supposed to have enough food to eat. However, in some p小题7: , the food is so little that  a lot of people died from hunger. T 小题8: China has tried hard to solve the problem of hunger over the past thirty years, the job is not f 小题9: yet. Food is important to us all. We can’t live without food. So it    is necessary for us to love food and try to eat up e 小题10:  on our plates. When we eat in restaurants, we should pack up the leftovers. We also need to tell other people to stop wasting food as soon as possible.

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幼儿园对幼儿实施保育和教育。幼儿园既有教育性质,也有()性质。

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中断供电将造成人身伤亡的用电负荷应为二级用电负荷。

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