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【简答题】
回答下列关于遗传和变异的问题: ( 1 )高等动物在产生精子或卵细胞的过程中,位同源染色体上的基因会发生 _________________ ,同源染色体的非姐妹染色单体之间可能会发生 _________________ ,这两种情况都可能导致基因重组,从而产生基因组成不同的配子。 ( 2 )假设物种的染色体数目为 2n ,在其减数分裂过程中,会出现不同的细胞,甲、乙 2 个模式图仅表示出了 Aa 、 Bb 基因所在的常染色体,那么,图甲表示的是 _________________ (填“初级精母细胞”、“次级精母细胞”或“精细胞”),图乙表示的是 _________________ (填“初级精母细胞”、“次级精母细胞”或“精细胞”)。 ( 3 )某植物的染色体数目为 2n ,其产生的花粉经培养可得到单倍体植株。单倍体是指 ________________ 。
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【简答题】Unit 2 听力L 3: A tour of the offices (2) Directions: After lunch Marty and Janet continue the tour of the offices. Choose T (true) or F (false) before these sentences.
【简答题】主干网和本地接入网的区别是什么?
【简答题】计算机网络中的主干网和本地接入网的主要区别是什么?
【单选题】Directions:choose the best answer to each of the questions you hear on the recording.
A.
Because it is a matter of courtesy.
B.
Because she doesn ’ t want to have the door slammed in her face.
C.
Because the door is too heavy for her to hold.
D.
Because she has had the bad experience of having a squashed nose
【判断题】Directions: If the relative pronoun can be omitted, please choose T; if not, choose F. 判断以下10个句子中的关系代词是否可以省略。如果可省略,请选择“正确”;如果不可省略,请选择“错误”。 We talked about the party which Natalia wants to organize for...
A.
正确
B.
错误
【简答题】Directions : Read the following passage and choose the most suitable heading from this list for each paragraph of the passage. There is one extra heading. A. Don't get too close B. Know your boss C. D...
【单选题】Directions:choose the best answer to each of the questions you hear on the recording.
A.
He thinks that there isn ’ t any significant difference in their social roles.
B.
He thinks that men and women should perform their own roles, in the family.
C.
He thinks that men and women are now switching their social roles
D.
He thinks that women are now playing more and more important roles in society.
【单选题】Directions: Choose the best translation for each sentence from the four choices marked A, B, C, and D, then write your answer on the Answer Sheet. The sales promotions haven ’ t been very successful t...
A.
今年的促销并不成功 。
B.
今年的促销十分成功 。
C.
今年的促销十分不成功 。
D.
今年的促销并不十分成功 。
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