| Three years ago, researchers announced the discovery
of human genes that were capable of turning ordinary cells into malignant ones.
The news met with some skepticism. Experts asked how a single gene could cause
such a dramatic change. Why does cancer take years or even decades to develop if
it is caused by such a simple and direct process In last week’s issue of the,
three research teams answered those questions by setting forth a new model for
understanding the role of oncogenes in cancer. Each group found that it does in fact take more than a single gene to produce cancer in normal cells. Teams at M. I. T and Cold Spring Harbor Laboratory on Long Island, N. Y. , reported that they could induce cancer in normal rat cells only by inserting at least two types of oncogene into the cells. "A single oncogene produced some changes, A. was caused by normal cells B. sometimes resulted from internal actions of the victim’s own body C. was a hereditary disease D. was a form of malignancy [单项选择]
[单项选择]Just a few years ago, a graduate from Brown University medical school had just an inkling about how to care for the elderly. Now, Brown and other U. S. medical schools are plugging geriatric (老年) courses into their curricula.
The U.S. Census Bureau projects the number of elderly Americans will nearly double to 71 million by 2030. The first members of the Baby Boomer generation, so named for the explosion in births in the years after World War Two, turn 65 in three years. In addition, people are living longer than ever. "The first ripples of the silver tsunami are lapping at the shores of our country, but there is not a coordinated or strategic response taking place in America," said Richard Besdine, who is direetor of the geriatrics division at Brown University medical school in Providence. Geriatries has never been a field of choice for young doctors. Elderly care doctors are paid less than most other physicians and surgeons and the aged can be hard to treat. The A. The large amount of the elderly has created a big problem in America. B. The number of the elderly has been growing beyond the capacity of America. C. America is not ready to cope with the growing number of the elderly. D. America is not the ideal place for the elderly to spend the rest of their lives. 我来回答: 提交
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