题干

下列为减少实验误差而采取的措施,正确的是(  )

选项

实验内容

减少实验误差采取的措施

A

对培养液中酵母菌数量进行计数

统计活体菌数可以不用染色

B

探索2,4一D促进插条生根的最适浓度

预实验细化浓度范围

C

调查人群中红绿色盲发生率

调查足够大的群体,随机取样并统计

D

比较有丝分裂细胞周期不同时期的时间长短

观察1个装片中的多个细胞并统计

A:A

B:B

C:C

D:D

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答案(点此获取答案解析)

C

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    Which comes first, happiness or money? Are richer people1? And 2how do people get richer? A recent study could tell you the answer.

    The study3thousands of teenagers and found that those who felt better about4as young adults 5 to have higher incomes by the time they 629. Those who were happiest earned an average of $8,000 more than those who were the most7.

    The researchers, from University College London and the University of Warwick, say that very gloomy(沮丧的)teens, no matter how tall or smart they were, earned 10% less than their peers8the happier ones earned 930% more.

    Happier teenagers have an easier time 10school, college and the job 11,12 because they always feel better about life. It may13 be true that happier people find it easier to make friends, who are often the key to homework help or networking.

    A report in June suggested that professional respect was more important than14in terms of workplace happiness. In August scientists announced that they had found the 15for happiness in women. Alas! The same gene doesn't appear to have16effect on men. And in October researchers in the UK and in the US announced that people who eat seven portions of fruit and vegetables a day report being the happiest.

    If it is really true that happier kids17being wealthier kids, is it necessary for parents to get their kids to do the homework? The fact is that 18 homework will make kids happy but surely hurt their grades. Studies do show19 that more education20better-paid jobs, which may give us a deep thought.