题干

下图甲表示某种细菌合成精氨酸的途径,图乙表示接种该细菌后可能出现的三种生长曲线。据图分析,下列有关描述中,正确的组合是

①.图甲显示了该细菌通过调节酶的活性来调节精氨酸的合成
②.从图甲可知,精氨酸的合成是由该细菌的3对等位基因共同控制的
③.图乙的结果可说明加大接种量能缩短细菌生长的调整期
④.精氨酸依赖型突变菌的产生,可能是因为控制酶1合成的基因发生突变

A:① 

B:②③④ 

C:③④ 

D:①②③④

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C

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    Looking back on the first twenty years of my life,I feel grateful to have been so healthy and happy.I'm happy because of many key factors(因素).____

    Health comes first for me, because without health everything else is meaningless. Imagine starting a career without good health. Imagine achieving anything without good health.____

    Good health is not enough to be happy.____Money obviously pays for the basic necessities of life—food, housing, clothing, etc.—but it is also necessary for other reasons. Money guarantees(保证) we always get good medical treatment when we fall ill. Besides, we can also use money for entertainment that can add to our quality of life.

    Family is another important factor in having a happy life because it provides the love, joy, and support that everyone needs. I love my family with all my heart. I get pleasure from their pleasure. I suffer when they suffer.____ They give me advice when I have misunderstandings with my friends. More importantly, they are always there to share everything with me.

    ____ As long as I stay healthy, work hard to earn enough money and share both good times and bad times with my family,I will always be the happiest girl in the world.

A. Money is the most important factor which contributes to a happy life.

B. These three factors are all that I need and want in this world.

C. My family help me get through worries, pressures and difficulties.

D. We still need to have money in today's society.

E. Finally, I'm quite thankful that I am healthy, wealthy and happy.

F. Clearly, good health is much more important than any other things of one's life.

G. They include my physical health, healthy finances and my family's happiness.