题干

科学家将人工合成的部分基因导入酵母菌细胞内并整合到酵母菌的染色体上,得到的重组酵母菌能存活且未见明显异常.关于该重组酵母菌的叙述正确的是(    )

A:改变了酵母菌种群的基因库

B:表现型主要受植入基因的控制

C:增加了酵母菌的物种多样性

D:改变了酵母菌的进化方向

上一题 下一题 0.0难度 选择题 更新时间:2019-05-30 01:10:33

答案(点此获取答案解析)

A

同类题4

阅读下面短文, 从短文后各题所给的四个选项(A、B、C、D)中, 选出可以填入空白处的最佳选项。

    Mickey was a nice, cheerful, optimistic boy. No one could remember ever having seen him 1; it seemed he didn't 2whatever people said to him. Even his teachers admired his good 3. It was so unusual that a story was going around that Mickey's 4 must be due to some special secret. They asked Mickey so much that he 5 his favorite teacher, Mr. Anthony, to tea one afternoon. When they had finished, Mickey 6 Mr. Anthony around the house. When Mickey opened his bedroom door, the teacher 7. The huge wall was a unique collage (拼贴画) of thousands of colors and shapes! It was the loveliest decoration Mr. Anthony had ever 8.

    “Some people at school think that I 9 think badly of anyone,” Mickey started to explain, “and that 10 at all bothers me, but that's not true at all. I'm just like anyone else. I used to get angrier than all the other kids. 11 years ago, with the help of my parents, I started a small collage. With every little piece I stuck on I added some bad thought or act.”

    It was 12. The teacher looked closely at the wall. In each one of the small 13 he could read “fool”, “silly”, “idiot”, “pain” , and a thousand other 14 things.

     “This is how I started 15 all my bad times into an opportunity to 16 to my collage. Now I like the collage so much that, each time someone makes me angry, I couldn't be17. They've given me a new piece for my work of 18.”

    That day, the teacher was impressed by Mickey's 19 to have an optimistic character. Without telling anyone, Mr. Anthony 20 his own collage and he would often recommend it to his students.