有一种人类中罕见的常染色体显性致病基因导致的疾病，在某海岛的人群中有很高的发病率。人类遗传学家在探讨该先天性疾病的高发病率成因时可能涉及到如下的哪种因素：

A.
该基因的突变率很高
B.
该海岛可能曾经发生过导致人类灾难的事件
C.
最初开发该海岛的少数移民
D.
该基因不受自然选择的作用

材料一20l0年7月，国务院总理温家宝与广大网友在线交流时说：“一个社会当财富集中在少数人手里，那么注定它是不公平的，这个社会也是不稳定的”。如果说把做大社会财富这个“蛋糕”看作是政府的责任，那么，把社会财富这个“蛋糕”分好，那就是政府的良知。
材料二2010年8月6日，人力资源和社会保障部劳动工资研究所所长苏海南表示，中国已基本具备条件，实现“年均工资增长15 %以上，五年左右就可以翻一番”的“国民收入倍增计划”。针对我国不同人群之间、城乡之间、地区之间，都发现了收入差距扩大的现象，有专家分析，“收入倍增计划”必须从底层做起，要靠最低工资水平的不断提高。
结合上述材料，运用《经济生活》知识回答：
(1)如何为“国民收入倍增计划”创造条件?
(2)如何在“国民收入倍增计划”中分好“蛋糕”? 查看习题详情和答案>>

这是一篇宣传环保的短文，内容介绍新泽西哈特威尔市卡蓬湖三十年前后的变化．三十年前湖畔鸟、兽成群，湖中游鱼成线；而现在由于污染所致，明镜的湖水成了暗褐色的泥浆，杂草丛生．那么如何才能恢复原貌呢？请看下文：

　　Thirty years ago, Lake Ponkapog in Hartwell, New Jersey, was full of life. Many birds and animals lived beside the water, which was full of fish. Now there are few birds, animals and fish. The lake water is polluted(污染的). It is in a colour of dirty brown, and it is filled with strange plants.

　　How did this happen? First, we must think about how water gets into Lake Ponkapog. When it rains, water comes into the lake from all around. In the past, there were forests all around Lake Ponkapog, so the rainwater was clean.

　　Now there are many homes around the lake. People often use chemicals(化学品) in their gardens. They use other chemicals inside their houses for cleaning or killing insects(昆虫). There are also many businesses. Businesses use chemicals in their machines or shops. Other chemicals fall onto the ground from cars or trucks. When it rains, the rainwater picks up all the chemicals from homes and businesses and then carries them into the lake. "They pollute the water and kill the animals.

　　Boats on the lake are also a problem. Lake Ponkapog is a popular place for motorboats. But oil and gas(油和汽) from boats often get into the lake. So more bad chemicals go into the water this way.

　　People in Hartwell are worried. They love their lake and want to save it. Will it be possible? A clean lake must have clean rainwater going into it. Clean rainwater is possible only if people are more careful about chemicals at home and at work. They must also be more careful about gas and oil and other chemicals on the ground. And they mustn't use motorboats any more on the lake. All these may change people's lives. Only then can Lake Ponkapog be a beautiful, clean lake again.

1．In the past, the water in Lake Ponkapog was made clean by ________.

[　　]

2．Chemicals from homes and businesses ________.

[　　]

A．are always clean

B．can help the animals

C．are good for the lake

D．get into the rainwater