题目内容
对维持细胞内、外水平衡有重要作用的是
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Clone Farm
Factory farming could soon enter a new era of mass production. Companies in the US are developing the technology needed to "clone" chickens on a massive scale. Once a chicken with desirable traits has been bred or genetically engineered, tens of thousands of eggs, which will hatch into identical copies, could roll off the production lines every hour. Billions of clones could be produced each year to supply chicken farms with birds that all grow at the same rate, have the same amount of meat and taste the same.
This, at least, is the vision of the US's National Institute of Science and Technology, which has given Origen Therapeutics of Burlingame, California, and Embrex of North Carolina $ 4.7 million to help fund research. The prospect has alarmed animal welfare groups, who fear it could increase the suffering of farm birds.
That's unlikely to put off the poultry industry, however, which wants disease resistant birds that grow faster on less food. "Producers would like the same meat quantity but to use reduced inputs to get there. " says Mike Fitzgerald of Origen. To meet this demand, Origen aims to "create an animal that is effectively a clone", he says. Normal cloning doesn't work in birds because eggs can't be removed and implanted. Instead, the company is trying to bulk-grow embryonic stem cells taken from fertilized eggs as soon as they're laid. "The trick is to culture the cells without them starting to distinguish, so they remain pluripotent. " says Fitzgerald.
Using a long-established technique, these donor cells will then be injected into the embryo of a freshly laid, fertilized recipient egg, forming a chick that is a "chimera". Strictly speaking, a chimera isn't a clone, because it contains cells from both donor and recipient. But Fitzgerald says it will be enough if, 95 percent of a chicken's body develops from donor cells. "In the poultry world, it doesn't matter if it's not 100 percent. " he says.
Another challenge for Origen is to scale up production. To do this, it has teamed up with Embrex, which produces machines that can inject vaccines into up to 50,000 eggs an hour. Embrex is now trying to modify the machines to locate the embryo and inject the cells into precisely the right spot without killing it.
In future, Origen imagines freezing stem cells from different strains of chicken. If orders come in for a particular strain, millions of eggs could be produced in months or even weeks. At present, maintaining all the varieties the market might call for is too expensive for breeders, and it takes years to bread enough chickens to produce the billions of eggs that farmers need.
Which statement is the best description of the new era of factory farming according to the first paragraph？
在窗体中有一个命令按钮Commandl，对应的事件代码如下： Private Sub Commandl_nter() Dim num As Integer Dim a As Integer Dim b As Integer Dim i As Integer For i＝1 To 10 num＝InputBox(“请输入数据：”，“输入”，1)
The huge scandal of cheating in TV game shows was not exposed until 40 years later in the
TV Game Shows
One of the most fascinating things about television is the size of the audience. A novel can be on the "best seller" lists with a sale of fewer than 100, 000 copies, hut a popular TV show might have 70 million TV viewers. TV can make anything or anyone well-known overnight.
This is the principle behind "quiz" or "game" shows, which put ordinary people on TV to play a game for prizes and money. A quiz show can make anyone a star, and it can give away thousands of dollars in the U.S. and almost everyone watched them. Charles Van Doren, an English instructor, became rich and famous after winning money on several shows. He even had a career as a television personality . But one of the losers proved that Charles Van Doren was cheating. It turned out that the show's producers who were pulling the strings, gave the answers to the most popular contestants (竞争者) beforehand . Why？ Because if the audience didn't like the person who won the game, they turned the show off. The result of this cheating was a huge scandal. Based on this story, a movie under the title "Quiz Show" is on 40 years later.
Charles Van Doren is no longer involved with TV. But game shows are still here, though they aren't taken as seriously. In fact, some of them try to be as ridiculous as possible. There are shows that send strangers on vacation trips together, or that try to cause newly-married couples to fight on TV, or that punish losers by humiliation (羞辱) them. The entertainment now is to see what people will do just to be on TV. People still win money, but the real prize is to be in front of an audience of millions.
TV can make a beggar world-famous overnight.
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