关于亚洲自然地理特征的叙述，正确的是（    ）

植物生理学家经研究发现：在光照条件下，O₂浓度较高时，植物叶肉细胞能吸收O₂，O ₂与C₃(RuBP，与卡尔文循环中C₅为同一种物质）结合形成C₃与C₂(—种二碳化合物），催化这一反应的酶(Rubisco)是一种兼性酶，它也能催化暗反应中C O ₂+C₅→2C₃的反应，其催化方向取决于环境中C O ₂和O ₂的比值。C₂在多种细胞器及多种酶的参与下，经一系列反应最终被氧化生成CO₂，如图所示。生理学家将植物的绿色细胞依赖光照，吸收O₂放出CO₂的过程称为光呼吸。请回答下列问题：

从甲乙两个城市分别随机抽取16台自动售货机，对其销售额进行统计，统计数据用茎叶图表示（如图所示），设甲乙两组数据的平均数分别为 ${\overline{x}}_{甲}$ ， ${\overline{x}}_{乙}$ ，中位数分别为m_甲，m_乙，则（   ）

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    Tommy is from a poor family. His father is a worker and he is often ill. Tommy hopes to be an artist, but everybody says it is not possible for him to be an artist and makes fun of his family and his dream. But Tommy never gives up.

    One day, he heard there was a drawing competition the following week, and anyone aged 13 and up was welcome. The winner would get 10,000 dollars and some art equipment(设备). He thought for a minute and decided to take part in the competition.

    That week seemed like the longest week in his life. Every day when he got home from school, a pencil and a piece of paper were the first things in his hands. He practiced drawing for a long time. Then, the day of the competition came. He finished his drawing quickly.

    After two weeks, Tommy got a letter. Tommy was too afraid to open the letter. At last he opened it slowly. Just as he read the first sentence, he began crying. However, they were not tears(眼泪) of sadness. They were tears of happiness.

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某有机物是一种强致癌物，其结构如图所示。1mol该化合物在一定条件下分别与H₂、NaOH溶液反应，最多消耗H₂和NaOH的物质的量分别为                     （   ）