题干

总体由编号为01,02,…,29,30的30个个体组成.利用下面的随机数表选取4个个体.选取方法是从随机数表第1行的第5列和第6列数字开始由左到右依次选取两个数字,则选出的第4个个体的编号为____

7806  6572  0802  6314  2947  1821  9800

3204  9234  4935  3623  4869  6938  7481

上一题 下一题 0.0难度 选择题 更新时间:2013-02-22 04:26:50

答案(点此获取答案解析)

29

同类题2

阅读理解

    First it was worry about second-hand smoke, now there's major concern over third-hand smoke which gets into hair, clothes, furniture or a car rather than directly from a cigarette or someone breathing it out.

    To be honest, I've always been worried about the health dangers of this even though I didn't know it had a name. My worry made me reluctant to let smokers hold my babies even though they didn't smoke in my house.

    Tests for its effects have been only carried out on mice, but I don't think they can be ignored. Researchers at California University last month suggested third-hand smoke (THS) could cause type 2 diabetes, liver and lung damage.

    They analyzed how people are affected by taking in smoke from another person's clothing, hair, home, or car. They say they can see an impact on the brain and liver. Lead author Manuela Martins-Green said: “Our goal was to decide the smallest amount of time required to cause physiological changes in mice when they are exposed(暴露) to THS.” This was done using an exposure system that is the same as human exposure.

    “We found THS exposure as early as one month caused liver damage. Exposure for two months lead to further molecular(分子的) damage, and at four to six months caused even more such damage. We also found the mice showed insulin resistance(抗胰岛素) after long-term exposure.”

    “THS is a hidden danger, a silent killer. Pollutants can be absorbed through the skin and through breathing.”

    “Although our research was not done on humans, people should be aware that hotel rooms, cars and homes that were used by smokers are very likely to be polluted with THS.” Martins-Green believes most people don't know they're being exposed to THS, or don't believe in the damage it can do.

    THS toxins(毒素) remain on surfaces for many years, and resist even strong cleaning agents.