问题 单项选择题

德国科学家贝特·魏茨泽克独立地推测太阳能源可能来自它的内部氢核聚变成氦核的热核反应,这甚至早于核裂变模型的提出。然而,与能够在室温下进行的裂变不同,聚变发生需要巨大能量。这是因为当两个带正电的氢原子核靠近的时候,根据“同性相斥”的原理,相互间的斥力将阻碍聚变的发生。要克服这种阻碍,只有两种途径:强大的引力,或上亿度的高温。然而,地球上并不具有太阳那样强大的引力场。因此,要想在地球上实现核聚变,只能依靠上亿度的高温。
下列关于“核聚变”的理解,符合原文意思的一项是:

A.太阳能源来自它的内部氢核聚变成氦核的热核反应
B.与能够在室温下进行的裂变不同,核聚变发生需要巨大能量
C.两个带正电的氢原子核靠近的时候,相互间的斥力能阻止聚变的发生
D.克服原子核之间的斥力发生核聚变,必须同时具备两个条件:强大的引力和上亿度的高温

答案

参考答案:B

解析: 太阳能源自它的内部氢核聚变成氦核的热核反应只是科学家的一种推测,并未得到完全证实,排除A。文段中只是说他们相互问的斥力将阻碍聚变的发生,并没有说肯定能够阻止聚变的发生。只要条件具备了,这种斥力是不难克服的,排除C。文中说的是只需具备其中一个条件即可,并不需要两个条件都要具备,排除D。

阅读理解

A super drug that could remove Alzheimer’s (老年痴呆症),heart disease and diabetes (糖尿病) and help people live to 100 is being developed by scientists. Their research is based on the identification of three genes that help prolong lives and prevent diseases which occur in old age. Medically controlling the proteins made by the “ longevity genes” will allow millions to live longer, predicts Dr Nir Barzilai.

Those whose DNA strongly features the three genes are 80 percent less likely to develop Alzheimer’s. The genes also fight against the deadly impact of smoking, poor diet, obesity and lack of exercise.

Already, several laboratories are working on a pill to imitate the benefits of the genes and Dr Barzilai thinks it could be tested within three years. The pill could remove some diseases that damage old age. “ The advantage of finding a gene that involves longevity is that we can develop a drug that will imitate exactly what this gene is doing,” he said.

Of the three longevity genes, two genes increase the production of so-called good cholesterol(胆固醇), which reduces the risk of heart disease. The third prevents diabetes. They were discovered by Dr Barzilai’s team while studying the DNA of 500 Ashkenazi Jews with an average age of 100. The chances of living that long are one in 10,000 but the group, which shared relatively few common ancestors, was 20 times more likely to hit the entury. Dr Barzilai said: “ 30 percent of them were obese or overweight and 30 percent smoked two acks of cigarettes a day for more than 40 years, however they can live to 100.”

But Andrew Ketteringham of the Alzheimer’s Society said: “Alzheimer’s disease, a most common disease, is likely to be caused by a combination of genetic disosition(遗传倾向), lifestyles and life events. Many genes are probably involved.

小题1:Some people are able to live to 100 years because of ______.

A.a magical medicine

B.three special genes

C.good living habits

D.longevity proteins小题2:Why does the discovery of the longevity genes mean a lot?

A.Because it can bring great benefits to scientific labs.

B.Because it can help people change their unhealthy genes

C.Because it helps produce a drug that can make people live longer.

D.Because it will help scientists build up a new branch of biology.小题3: From Paragraph 4 we can infer that ________.

A.longevity genes can create good cholesterol.

B.the volunteers share some common ancestors

C.bad habits are likely to have no effect on the volunteers

D.longevity genes protect the volunteers against bad habits小题4:What is Andrew Ketteringham’s attitude toward the study?

A.Positive

B.Negative

C.Critical

D.Cautious

多项选择题