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What is cloning? Are there different types of cloning? _____71____ Actually, there are different technologies which can be used for other purpose besides producing the genetic twin of another organism. A basic understanding of the different types of cloning is key to talking an informed stance on current public policy issues and making the best possible personal decisions. The following three types of cloning technologies are usually performed; recombinant DNA technology or DNA cloning, reproductive cloning, and therapeutic cloning. ___72_____ Scientists have been cloning animals for many years. In 1952, the first animal, a tadpole, was cloned. ___73_____ Since Dolly, researchers have cloned a number of large and small animals including sheep, goats, cows, mice, pigs, cats, rabbits, and a gaur. ____74____ Hundreds of cloned animals exist today, but the number of different species is limited. ____75____ Some species may be more resistant to somatic cell nuclear transfer than others. The process of stripping the nucleus from an egg cell and replacing it with the nucleus of a donor cell is a traumatic one, and improvements in cloning technologies may be needed before many species can be cloned successfully. A.What animals have been cloned? B.All these clones were created using nuclear transfer technology C.When the media report on cloning in the news, they are usually talking about only one type called reproductive cloning. D.Recently Chinese scientists have also successfully cloned mammals such as an ox. E.       Cloning is making a genetic copy of something else. F.       Attempts at cloning certain species such as monkeys, chickens, horses, and dogs, have been unsuccessful. G.       Before the creation of Dolly, the first mammal cloned from the cell of an adult animal, clones were created from embryonic cells.
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参考答案:
举一反三
【单选题】显示文件类型的命令是什么?
A.
find
B.
find
C.
pwd
D.
ls -F
【简答题】AVR单片机的DDRX寄存器的作用是 . PORTX寄存器的作用是 .
【简答题】(1)从30mL0.5mol?L -1 NaOH溶液中取出10mL:这10mL溶液的物质的量浓度是______mol?L -1 ,其中的溶质质量是______g. (2)将30mL0.5mol?L -1 NaOH溶液加水稀释到500mL,稀释后溶液中NaOH的物质的量浓度是______mol?L -1 . (3)现有体积相同的NaCl、MgCl 2 、AlCl 3 三种溶液,分别加入足量的硝酸银溶...
【单选题】除夕吃饺子有()之意,以寄托人们对新的一年的祈望。
A.
“喜庆团圆”
B.
“吉祥如意”
C.
“招财进宝”
D.
以上都有
【判断题】力的作用可以改变物体的运动状态,但不能改变物体的形状。()
A.
正确
B.
错误
【判断题】巢元方主撰的《诸病源候论》是我国现存最早的病源证源症候学专著
A.
正确
B.
错误
【单选题】在df命令中,显示文件系统的类型的参数是:
A.
-T
B.
-t
C.
-h
D.
-f
【单选题】显示文件类型的命令是什么?
A.
find
B.
file
C.
pwd
D.
ls -F
【单选题】对下列现象解释不正确的是(  )
A.
运动员把弓拉弯,说明力能改变物体的形状
B.
用硬纸片把盛满水的杯子的杯口盖上,再使杯口向下,硬纸片不会掉下,水不会流出,主要是水粘住了纸片
C.
刚从游泳池中出来的人,风一吹,浑身发抖,是因为液体蒸发具有致冷的作用
D.
影子是光在直线传播过程中,遇到不透明的物体把部分光挡住形成的
【单选题】下列叙述主要说明力能改变物体的形状的是
A.
用力拉弓,弓弯了
B.
用力蹬自行车,自行车向前
C.
用力垫球,球飞出去
D.
瞄准射击,子弹飞出去
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