题目

Part B (10 points)

Farm-raised pigs are dirty, smelly animals that get no respect. They’re also an environmental hazard. Their manure contains phosphorus, which, when it rains, runs off into lakes and estuaries, depleting oxygen, killing fish, stimulating algae overgrowth and emitting greenhouse gases.

______. Pigs provide more dietary protein, more cheaply, to more people than any other animal. Northern Europe still maintains the highest pig-to-human ratio in the world (2-1 in Den- mark), but East Asia is catching up. During the 1990s, pork production doubled in Vietnam and grew by 70 percent in China— along densely populated coastlines, pig density exceeds 100 animals per square kilometer. The resulting pollution is “threatening fragile coastal marine habitats including mangroves, coral reefs and sea grasses,” according to a report released in February by the Food and Agriculture Organization of the United Nations.

As it turns out, there is a solution to the pig problem, but it requires a change of mind-set among environmentalists and the public. 42. ______.

The Enviropig is one of many new technologies that are putting environmentalists and organic-food proponents in a quandary: should they remain categorically opposed to genetically modified (GM) foods even at the expense of the environment? 43. ______. The most significant GM applications will be ones that help alleviate the problem of agriculture, which accounts for 38 percent of the world’s landmass and is crowding out natural ecosystems and species habitats. GM crops that can be produced more efficiently would allow us to return land to nature.

______. U.S. Department of Agriculture scientist Eliot Herman has already created a less-allergenic soybean — an important crop for baby foods. Through genetic surgery, Herman turned off the soy gene responsible for 65 percent of allergic reactions. Not only was the modified soy less allergenic in tests but, as Herman explained, “the yield looks perfectly normal, plants develop and grow at a normal rate and they seem to have the same kinds of protein, oil and other good stuff in them.” Other scientists have reported promising results in shutting off allergy-causing genes in peanuts and shrimp. Should these advances be turned into products, organic soy or peanut products will be certifiably more dangerous to human health than comparable nonorganic products.______. In this climate, much of the needed research isn’t being pursued. Chances are, farmers will continue to grow their polluting organic pork, their allergenic organic soy and their neurotoxin-sprayed organic apples. Worse still, they will make sure that no one else gets a choice in the matter of improving the conditions of life on earth — unless, that is, others rise up and demand an alternative.

[A] Two Canadian scientists have created a pig whose manure doesn’t contain very much phosphorus at all. If this variety of pig were adopted widely, it could greatly reduce a major source of pollution. But the Enviropig, as they call it, is the product of genetic modification — which is anathema to many Westerners.

[B] In fact, although all commonly used pesticides dissipate so quickly that they pose a miniscule health risk to consumers, allergic food reactions to natural products kill hundreds of children each year. Genetically modified foods could greatly reduce this risk.

[C] Canadian biologists Cecil Forsberg and John Phillips, for instance, have constructed a novel DNA molecule that, when planted in a pig embryo, imbues the Enviropig with the ability to secrete a phosphorus extracting enzyme in its saliva. The results so far are dramatic — the new pigs can extract all the phosphorus they need from grain alone, without the phosphorus supplements that farmers now use. This reduces the phosphorus content of their manure by up to 75 percent.

答案
查看答案
相关试题

国际收支危机(Balance of Payments Crises)

在含有n个空链域的二叉链表中有_______个结点,n个结点的二又链表中有个空链域。

货币需求函数L=0.4Y-10r,并且价格水平不变(P=1)

(1)若名义货币供给量为300,求货币供求均衡时LM曲线的表达式;

(2)若名义货币供给量为300,求货币供求均衡时LM曲线的表达式,并与(1)中所求LM曲线比较其不同;

(3)对于(2)中LM曲线,若r=20,Y=2000,货币供求是否均衡?

简述两种局域网计算机之间实现网络资源共享的方法以及利弊。

结合图形说明增加货币供应量对宏观经济的短期和中长期的影响。

最新解答的试题
付款人在进行付款时无()

A.形式审查义务

B.实质审查义务

C.附带审查义务

D.票据外有关事项的审查义务
根据《公司法》的规定,有限责任公司下列人员中,可以提议召开股东会临时会议的是()。
A.总经理B.人数过半数的股东C.监事会主席D.人数为半数的董事
关于股份有限公司中的监事会,下列说法错误的是()

A.监事会负责提议聘请或更换外部审计机构B.监事会主席和副主席由全体监事过半数选举产生C.监事会中的职工代表的比例不得低于三分之一D.监事会应至少每6个月召开一次会议
三北精神的科学内涵
阿里巴巴提供了“企业名称认证”“企业身份认证”不同种类的认证,可以根据自身的