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阅读材料，回答题。
Alpha Particle
From decaying radon （氡） atoms can destroy the living cells they strike and increase the likelihood that those cells will later become cancerous.Researchers have now directly demonstrated that neighboring cells not suffering direct hits can be harmed， too. They"ve also taken a step toward showing how this type of radiation，called alpha particles， indirectly hurts those bystanders.
Radon derives from the decay of uranium （铀） and seeps naturally into the air from the ground.lt"s the primary environmental source of alpha particles， which contribute to cancer risk by causing aberrations （失常）in DNA.Alpha particles from inhaled radon are second only to smoking as a cause of lung cancer.
Because a person"s exposure to alpha particles typically is low， researchers have had to estimate public health threats from radon by guess from the effects of higher doses of alpha radiation.Such data comes primarily from studies of survivors of the atomic bombs that destroyed Hiroshima and Nagasaki in Japan. The customary extrapolation （推测 ） assumes that cancer risk is proportional to the dose of radiation even at low doses.
Radiation"s effects in cell structure don"t necessarily reflect what happens in "a whole organism， with its full range of defense repair mechanisms， " says Duport.Processes such as DNA repair and cell death triggered by radiation damage could cancel the effect on by stander cells observed in the lab， he suggests.
Furthermore， while a bystander effect can contribute to cancer， other cell-to-cell interactions in living tissue "may relieve increased risk." says Barry Michael， a radiation biophysicist at the Gray Cancer Institute in Northwood， England.One of these interactions halts cell division and hence cancer. "The jury is still out on whether cell-to-cell effects lead to a greater or lower risk， " Michael says.
The passage‘s main topic is__________. 查看材料
A.The experiment done by researchers
B.Uranium is the key killer of neighboring cells
C.Cell-to-cell interaction can make up for the hurt cells
D.Bystander cells can be indirectly damaged by alpha particles
更多“阅读材料，回答题。Alpha ParticleFrom decaying radon ...”相关的问题
第1题
Alpha Particle
From decaying radon （ 氡） atoms can destroy the living cells they strike and increase the likelihood that those cells will later become cancerous.Researchers have now directly demonstrated that neighboring cells not suffering direct hits can be harmed， too. They"ve also taken a step toward showing how this type of radiation，called alpha particles， indirectly hurts those bystanders.
Radon derives from the decay of uranium （ 铀） and seeps naturally into the air from the ground.lt"s the primary environmental source of alpha particles， which contribute to cancer risk by causing aberrations （失常）in DNA.Alpha particles from inhaled radon are second only to smoking as a cause of lung cancer.
Because a person"s exposure to alpha particles typically is low， researchers have had to estimate public health threats from radon by guess from the effects of higher doses of alpha radiation.Such data comes primarily from studies of survivors of the atomic bombs that destroyed Hiroshima and Nagasaki in Japan. The customary extrapolation （ 推测 ） assumes that cancer risk is proportional to the dose of radiation even at low doses.
Radiation"s effects in cell structure don"t necessarily reflect what happens in "a whole organism， with its full range of defense repair mechanisms， " says Duport.Processes such as DNA repair and cell death triggered by radiation damage could cancel the effect on by stander cells observed in the lab， he suggests.
Furthermore， while a bystander effect can contribute to cancer， other cell-to-cell interactions in living tissue "may relieve increased risk." says Barry Michael， a radiation biophysicist at the Gray Cancer Institute in Northwood， England.One of these interactions halts cell division and hence cancer. "The jury is still out on whether cell-to-cell effects lead to a greater or lower risk， " Michael says.
The passage‘s main topic is__________. 查看材料
A.The experiment done by researchers
B.Uranium is the key killer of neighboring cells
C.Cell-to-cell interaction can make up for the hurt cells
D.Bystander cells can be indirectly damaged by alpha particles
第2题
A.decaying uranium
B.decaying radon atoms
C.air from the ground
D.radiation particles
第6题
A．The moral decaying deserves more research by sociologists.
B．Marriage break-up stems from sex inequalities.
C．Husband and wife have different expectations from their marriage.
D．Conversational patterns between man and wife are different.
第7题
A．The moral decaying deserves more research by sociologists .
B．Marriage break-up stems from sex inequalities.
C．Husband and wife have different expectations from their marriage.
D．Conversational patterns between man and wife are different.
第8题
A．The moral decaying deserves more research by sociologists .
B．Marriage break-up stems from sex inequalities.
C．Husband and wife have different expectations from their marriage.
D．Conversational patterns between man and wife are different.
第9题
A．The moral decaying deserves more research by sociologists.
B．Marriage break-up stems from sex inequalities.
C．Husband and wife have different expectations from their marriage.
D．Conversational patterns between man and wife are different.
第10题
A．It is natural for mountain lakes to have acidity levels higher than those of other lakes.
B．The harmful effects of increased acidity levels in lakes have been greatly underestimated.
C．Acid rain is found in urban and heavily industrialized regions of the country.
D．There is much disagreement among soil scientists about the causes of acid rain.
E．While plant life remains, acid rain significantly increases the amount of decaying organic matter in natural environments.
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