“加碘盐”本来是用来预防“大脖子病”的日用调味品,其预防的效果十分显著.近来又有

题型:问答题

问题:

“加碘盐”本来是用来预防“大脖子病”的日用调味品,其预防的效果十分显著.近来又有传言,说此种盐还能防御核辐射,因此最近日本福岛核电站发生核泄漏事故后出现了抢购加碘盐的风潮.那末加碘盐究竟能不能预防核辐射呢?请你通过下面的计算回答此问题.

资料:①当核电站因发生事故引起核泄漏时,周围居民可服用含碘药剂来预防核辐射中碘131带来的伤害,成年人的建议服用量为每次100毫克“碘”,服用后可以在24小时内持续保护你免受碘131的伤害;②加碘盐中加入的碘剂是碘酸钾(其中含“碘”59.4%),含量为20~40毫克/公斤.

问:如果以服用加碘盐的方法来预防核辐射,每天须服用多少?这种方法可行吗?说明理由.

考点:物质组成元素的质量分数
题型:问答题

In the past 300 years, more than 130 species of animals have become extinct. One of these extinct species is the passenger pigeon(旅鸽). At one time there were millions of these birds in North America, but now there are none. The last one died in the Cincinnati Zoo in 1914. Another extinct animal is the cape lion(西非狮). The animal has been extinct since 1860.

What cause animals to become extinct? Too much hunting is one cause; pollution is another.

Governments around the world have begun to protect wild animals in danger. In the United States, the US Fish and Wildlife Service is responsible for(承担义务)endangered animals. It has listed nearly 200 species of endangered animals in North America.

小题1:The underlined word “extinct” in the first sentence probably means “         ”.

A.ill

B.dying out

C.becoming

D.changing小题2:There were many cape lions in North America          .

A.last century

B.in the twentieth century

C.more than one hundred years ago

D.in 1914小题3:       isn’t the reason for the extinction of wild animals in North America.

A.The pollution

B.Too much killing

C.Too much hunting

D.The war小题4:Three are        species of wild animals in danger listed by the US Fish and Wildlife.

A.less than 130

B.about 200

C.over 300

D.nearly 300小题5:The best title of this passage should be “       ”.

A.A sad story

B.Endangered animals in North America

C.Wild animals become extinct

D.The US Fish and Wildlife Service

题型:问答题

古代的生物学研究,主要是通过观察对生物进行描述,从而进行定性和分类,因此可以称为

 [ ]

A.实验生物学

B.进化生物学

C.描述生物学

D.理论生物学

题型:问答题

小明打算做一个观察唾液淀粉酶消化作用的实验,他在1号、2号两只试管中分别加入2mL淀粉糊,请你帮他继续完成实验:

(1)该实验的实验组是______号试管,对照组是______号试管.

(2)本实验用37℃水浴,是因为______.

(3)l号、2号试管冷却后加入碘液,出现的现象分别是:1号试管______,2号试管______.

(4)发生该现象的原因分别是:l号试管______,2号试管______,从而得出的结论是:______.

题型:问答题

已知蜡烛的主要成分是石蜡.由蜡烛燃烧后生成水和二氧化碳的实验事实,判断石蜡中一定含有哪些元素?

题型:问答题

弹性、塑性、强度、硬度、冲击韧度和疲劳强度

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