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问题 单项选择题

DNA复制时，序 * * ’-TpApGpAp-3’将合成下列哪种互补结构（）。

A.5’-TpCpTpAp--3’

B.5’-ApTpCpTp--3’

C.5’-UpCpUpAp--3’

D.5’-GpCpGpAp--3’

E.3’-TpCpTpAp--3’

答案

参考答案：A

选择题

在汉代，人们把玉门关、阳关以西，包括今天新疆以及更远的地区称为西域。下列属于中国古代政府加强对今天新疆地区管理的举措有

①西汉政府设立西域都护府②汉武帝平定准噶尔贵族叛乱③清政府在该地区实施“改土归流”④清朝平定天山南路的回部贵族叛乱  [ ]

A．①③

B．②③

C．①④

D．②④
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单项选择题

The Chanterelle, a type of wild mushroom, grows beneath host trees such as the Douglas fir, which provide it with necessary sugars. The underground filaments of Chanterelles, which extract the sugars, in turn provide nutrients and water for their hosts. Because of this mutually beneficial relationship, harvesting the chanterelles growing beneath a Douglas fir seriously endangers the tree.
Which of the following, if true, casts the most doubt on the conclusion drawn above

A．The number of wild mushrooms harvested has increased in recent years.

B．Chanterelles grow not only beneath Douglas firs but alto beneath other host trees.

C．Many types of wild mushrooms are found only in forests and cannot easily be grown elsewhere.

D．The harvesting of wild mushrooms stimulates future growth of those mushrooms.

E．(E) Young Douglas fir seedlings die without the nutrients and water provided by Chanterelle filaments.
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