| 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]From where will the researcher get the permission for the new drug
A. The American Government. B. The City Hospital C. The Medical Research Institute D. The U. S. Food and Drug Administration. [单项选择]When a researcher use grounded theory practice in collecting data, and categorizes data into patterns as the primary basis for organizing and reporting results, he is doing______.
A. qualitative research B. qualitative research C. synchronic research D. diachronic research [单项选择]
A researcher studying drug addicts found that, on average, they tend to manipulate other people a great deal more than nonaddicts do. The researcher concluded that people who frequently manipulate other people are likely to become addicts. A. After becoming addicted to drugs, drug addicts learn to manipulate other people as a way of obtaining drugs B. When they are imprisoned, drug addicts often use their ability to manipulate other people to obtain better living conditions C. Some nonaddicts manipulate other people more than some addicts do D. People who are likely to become addicts exhibit unusual behavior patterns other than frequent manipulation of other people E. The addicts that the researcher studied were often unsuccessful in obtaining what they wanted when they manipulated other people [填空题]Researcher’s studies indicated that the couples who owned a pet can ______.
[填空题]A researcher says lead in the environment could be a major cause of violence by young people. Doctor Herbert Needleman is a professor at the University of Pittsburgh School of Medicine in Pennsylvania. He says the (36) of lead in the brain changes the neurons that control actions and that can cause a person to act in antisocial and (37) ways.
Lead is a metal that is (38) dangerous to babies and young children. They can get it into their bodies by breathing or (39) lead dust, or by eating soil or pieces of lead paint. Children with high levels of lead can (40) brain and nervous system damage, learning (41) , slow growth, headaches and hearing loss. In the 19th century, Doctor Needleman found lower scores on (42) tests even in children who did not have such signs of lead (43) . After that, lead was removed from gasoline and paint in the United States. Yet many homes still have old lea 我来回答: 提交
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