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ic 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, say, 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.
　　41．Which statement is the best description of the new era of factory farming according to the first paragraph?
　　A. Eggs are all genetically engineered.
　　B. Thousands of eggs are produced every hour.
　　C. Cloned chickens are bulk-produced with the same growth rate, weight and taste.
　　D. Identical eggs can be hatched on the production lines.
　　42. Which institution has offered $4.7 million to fund the research?
　　A. The US’s National Institute of Science and Technology.
　　B. Origen therapeutics of Burlingame, California.
　　C. Embrex of North Carolina.
　　D. Animal welfare groups.
　　43. In the third paragraph, by saying “Producers would like the same meat quantity but to use reduced inputs to get there.” Mike Fitzgerald means that he wishes
　　A. chickens’ quality could be maintained but with less investment.
　　B. chickens’ taste could be improved but at less costs.
　　C. chickens’ growth rate could be quickened but with less inputs.
　　D. chickens could grow to the same weight but with less feed.
　　44. Which of the following statements about Origen and Embrex is correct according to the fifth paragraph?
　　A. Origen and Embrex will jointly invent machines to increase production.
　　B. Origen wants to purchase an efficient donor cells injecting machine.
　　C. Origen has joined hands with Embrex in producing cell-injecting machines.
　　D. Origen is the leading company in producing embryo-locating machines.
　　45. The technology of freezing stem cells from different strains of chicken can do all the following EXCEPT that
　　A. farmers can order certain strains of chicken only.
　　B. Origen can supply all the strains of chicken the market might need.
　　C. chicken farmers order certain strains of chicken for economic reasons.
　　D. chicken farmers can be supplied with whatever strain they need.

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　　The Spread of Microorganisms
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