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【简答题】
Have you seen Jurassic Park? In this film, scientists use DNA kept for tens of millions of years to clone dinosaurs. They find trouble, however, when they realize that the cloned creatures are smarter and more dangerous than expected. That’s nothing more than a fiction. But could we really clone endangered animals? To date, the most successful att empt to do so was the cloning of a gaur, a rare ox-like animal from southeast Asia. Scientists used a cow to bring the cloned baby gaur, named Noah. Two days after birth, however, Noah died from a common bacterial infection. Other endangered species that may be cloned include the African bongo antelope (邦戈羚羊), the Sumatran tiger, the cheetah (猎豹), and the giant panda.     Next, could we really clone extinct animals? In theory? Yes. To do this, you need a well-kept source of DNA from the extinct animals such as wool mammoth (), Tasmanian tiger, or even dinosaur, and a closely related species, still living, which could serve as a surrogate mother. In reality? Probably not. On the one hand, it’s not likely that extinct animals’ DNA could survive undamaged for such a long time. Cloning extinct animals as wool mammoth, Tasmanian tiger, or dinosaur is much more difficult due to the lack of properly well-preserved DNA. On the other hand, for example, a gaur can have a cow as a surrogate mother, defin itely not a monkey. But what about an extinct animals as unique as the panda? What species could possibly serve as a surrogate mother? Cloning presents many exciting possibilities. However, even if extinct animals are brought back, they could not survive in today’s world. Not only do most extinct animals have no habitat to love in, but the other plants and animals they depended on for food may also be gone as well. 1. It can be learned from the text that ________. A. scientists have cloned the African bongo antelope B. both the cheetah and the giant panda live in Asia C. the gaur lives in Asia and is endangered D. the gaur is an extinct species 2. The underlined words “a surrogate mother” probably refer to a female who ----- A. contributes its eggs to another female  B. gives birth to a baby for another female C. gives birth to a baby of its own        D. cannot give birth to a baby 3. The difficulty in cloning an extinct species is the lack of ______. A. both the well-preserved DNA and plants to live on B. both the habitat to live in and the well-preserved DNA C. both habitat to live in and plants to live on D. both the well-preserved DNA and a surrogate mother 4. In the author’s opinion, it is possible that ______. A. some extinct species may be cloned, but not survive B. extinct species may be cloned and easily survive C. a gaur can hav e a monkey as a surrogate mother D. all the extinct species may be cloned 5.Today , have scientists  cloned  dinosaus? A .Yes    B .No    C .A lot  D.Only one.
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【多选题】如图所示,一弹性轻绳(绳的弹力与其伸长量成正比)一端固定在A点,弹性绳自然长度等于AB,跨过由轻杆OB固定的定滑轮连接一个质量为m的绝缘带正电、电荷量为q的小球。空间中还存在着水平向右的匀强电场(图中未画出),且电场强度E= 。初始时
A.
B、C在一条竖直线上,小球穿过水平固定的杆从C点由静止开始运动,滑到E点时速度恰好为零。已知C、E两点间距离为L,D为CE的中点,小球在C点时弹性绳的拉力为 mg,小球与杆之间的动摩擦因数为0.5,弹性绳始终处在弹性限度内。下列说法正确的是 小球在D点时速度最大
B.
若在E点给小球一个向左的速度v,小球恰好能回到C点,则v=
C.
弹性绳在小球从C到D阶段做的功等于在小球从D到E阶段做的功
D.
若保持电场强度不变,仅把小球电荷量变为2q,则小球到达
E.
点时的速度大小v=
【单选题】主肺动脉窗的横断层面上不出现
A.
右肺尖段
B.
右肺前段
C.
有肺后段
D.
左肺尖后段
E.
肺前段
【单选题】如图所示,一小球从A点由静止开始沿斜面向下做匀变速直线运动,若到达B点时速度为v,到达C点时速度为2v,则AB∶BC等于( )
A.
1∶1
B.
1∶2
C.
1∶3
D.
1∶4
【判断题】钠和氯两种元素主要存在于体液和软组织中,是维持细胞外液渗透压平衡与酸碱平衡的主要离子。
A.
正确
B.
错误
【单选题】存在于细胞外液中的主要离子是( )。
A.
碳酸氢盐和K+
B.
硫酸盐和磷酸盐
C.
Cl-和Na+
D.
Cl-和K+
【单选题】如图所示,一小球从 A 点由静止开始沿斜面做匀变速直线运动,若到达 B 点时速度为 v ,到达 C 点时速度为 2 v ,则 AB ∶ BC 等于 ( )
A.
1 ∶ 1
B.
1 ∶ 2
C.
1 ∶ 3
D.
1 ∶ 4
【简答题】以你熟悉的原料,分别设计3种罐头制品的加工工艺,包括肉类罐头制品、水产罐头制品、果蔬罐头制品,写出其工艺流程,并简述操作要点。(作业模式可参照教材P317红烧扣肉罐头,本章在线课程的案例分析也有相关加工视频,可作为做题的参考资料)
【单选题】如图所示,一小球从A点由静止开始沿斜面做匀变速直线运动,若到达B点时速度为υ,到达C点时速度为2υ,则AB、BC段的距离之比为()。
A.
1:1
B.
1:2
C.
1:3
D.
1:4
【简答题】氯化钠是人的正常生理活动必不可少的一种物质。人体内所含的氯化钠大都分以离子形式存在于体液中。 离子对维持细胞内外正常水分布和促进细胞内外物质交换起主要作用; 离子是胃液中的主要成分,具有促生盐酸、帮助消化增进食欲的作用。根据盐的组成里所含阴、阳离子的特点,可将盐分类并称某盐。例如氯化钠根据所含阳离子分类,属于 盐。
【单选题】如图所示,一小球从A点由静止开始沿斜面向下做匀变速直线运动,若到达B点时速度为v,到达C点时速度为2v,则xAB∶xBC等于()
A.
1∶1
B.
1∶2
C.
1∶3
D.
1∶4
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