劍橋雅思8-第三套試題-閱讀部分-passage(已修改)
2025-01-30 05:38 本頁面
【正文】 劍橋雅思8第三套試題閱讀部分PASSAGE 3閱讀真題原文部分: READING PASSAGE 3 You should spend about 20 minutes on Questions 27—40, which are based on Reading Passage 3 on the following pages. Questions 2732 Reading Passage 3 has seven paragraphs, AG. Choose the correct heading for paragraphs BG from the list of headings below. Write the correct number, ix, in boxes 2732 on your answer sheet. List of Headings i The biological clock ii Why dying is beneficial iii The ageing process of men and women iv Prolonging your life v Limitations of life span vi Modes of development of different species vii A stable life span despite improvements viii Energy consumption ix Fundamental differences in ageing of objects and organisms x Repair of genetic material Example Answer Paragraph A v 27 Paragraph B 28 Paragraph C 29 Paragraph D 30 Paragraph E 31 Paragraph F 32 Paragraph GHOW DOES THE BIOLOGICAL CLOCK TICK? A Our life span is restricted. Everyone accepts this as 39。biologically39。 obvious. 39。Nothing lives for ever!39。 However, in this statement we think of artificially produced, technical objects, products which are subjected to natural wear and tear during use. This leads to the result that at some time or other the object stops working and is unusable (39。death39。 in the biological sense). But are the wear and tear and loss of function of technical objects and the death of living organisms really similar or parable? B Our 39。dead39。 products are 39。static39。, closed systems. It is always the basic material which constitutes the object and which, in the natural course of things, is worn down and bees 39。older39。. Ageing in this case must occur according to the laws of physical chemistry and of thermodynamics. Although the same law holds for a living organism, the result of this law is not inexorable in the same way. At least as long as a biological system has the ability to renew itself it could actually bee older without ageing。 an organism is an open, dynamic system through which new material continuously flows. Destruction of old material and formation of new material are thus in permanent dynamic equilibrium. The material of which the organism is formed changes continuously. Thus our bodies continuously exchange old substance for new, just like a spring which more or less maintains its form and movement, but in which the water molecules are always different. C Thus ageing and death should not be seen as inevitable, particularly as the organism possesses many mechanisms for repair. It is not, in principle, necessary for a biological system to age and die. Nevertheless, a restricted life span, ageing, and then death are basic characteristics of life. The reason for this is easy to recognise: in nature, the existent organisms either adapt or are regularly replaced by new types. Because of changes in the genetic material (mutations) these have new characteristics and in the course of their individual lives they are tested for optimal or better adaptation to the environmental conditions. Immortality would disturb this system it needs room for new and better life. This is the basic problem of evolution. D Every organism has a life span which is highly characteristic. There are striking differences in life span between different species, but within one species the parameter is relatively constant. For example, the average duration of human life has hardly changed in thousands of years. Although more and more people attain an advanced age as a result of developments in medical care and better nutrition, the characteristic upper limit for most remains 80 years. A further argument against the simple wear and tear theory is the observation that the time within which organisms age lies between a few days (even a few hours for unicellular organisms) and several thou
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