下列各项的结果中,不可能出现3:1比值的是() A.15N标记的DNA在14N培养液

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问题:

下列各项的结果中,不可能出现3:1比值的是()

A.15N标记的DNA在14N培养液中复制三次,子代中不含15N的DNA与含15N的DNA数量之比

B.黄色圆粒豌豆(YyRr)与黄色圆粒豌豆(YyRR)杂交子代的性状分离之比

C.酵母菌有氧呼吸与无氧呼吸强度相同时吸入的O2与产生的CO2总量之比

D.动物的一个初级卵母细胞经减数分裂形成的极体与卵细胞的数目之比

考点:高中生物呼吸作用呼吸作用题库
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阅读理解。

     One day at a park, a woman sat down next to a man on a bench (长椅) near a playground. “That’s my son over there,” she said, pointing to (指着) a little boy in a red sweater. 

     "He’s a lovely boy,” the man said. “That’s my daughter on the bike in the white dress.” Then, looking at his watch, he called to his daughter, “We have to leave for home now, Rosa.”

     "Just five minutes, Dad,” Rosa said, “Please, just five more minutes.”

     The man agreed and Rosa went to ride his bike happily. Five minutes later, the father stood and called again to his daughter, “Time to go now?”

     "Five more minutes, Dad,” Rosa said again, “Just five more minutes.”

     The man smiled and said, “OK.”

     "Oh, you are really a patient father,” said the woman.

     The man smiled and then said, “Her elder brother Tommy died (死) in a traffic accident (事故)last year when he was riding his bike near here,” the man said,  “I never spent much time with Tommy and now I’d like to give anything for just five more minutes with him. I vowed (发誓) not to make the same mistake(错误) with Rosa. She thinks she has five more minutes to ride her bike. In fact, I get five more minutes to watch her play.”

1. The woman’s son was wearing _________.

A. a red T-shirt

B. a red sweater

C. a white sweater

D. a white dress

2. From the article, we know that Tommy was _________.

A. the man’s son

B. the woman’s son

C. Rosa’s younger brother

C. the man’s elder brother

3. The underlined word “patient” means_________.

A. 严格的

B. 勤劳的

C. 有耐心的

D.积极的

4. Which of the following sentences is TRUE?

A. The man’s daughter and her brother played at the park.

B. Rosa agreed to go home when her father called her the first time.

C. The woman felt sorry that she didn’t spend any time with her son.

D. The man learned a lot from Tommy’s death(死亡).

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证券组合的期望收益率是使可能的预测值与实际值的平均偏差达到最小的点估计值。()

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乳痈初起可选用哪种外用药:

A.八二丹

B.七三丹

C.白玉膏

D.红灵膏

E.金黄散

题型:单项选择题

糖皮质激素禁用于胃溃疡是因为()

A.水、钠潴留 

B.促进胃酸分泌 

C.抑制免疫功能 

D.抑制蛋白质合成 

E.兴奋中枢神经系统

题型:单项选择题

关于健康教育与健康促进关系的正确表述是()

A.健康促进在健康教育中起主导作用

B.健康促进减弱了健康教育的力度

C.健康教育和健康促进是相同的概念

D.健康教育比健康促进内涵更广泛

E.健康教育是健康促进的重要组成部分

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