• NOT GIVEN if it is impossible to say what the writer thinks about this 21
  • Few words to say about this book




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    THE-BIBLE-OF-IELTS-READING-BOOK

    Questions 21-23 
    YES
    if the statement agrees with the claims of the writer
    NO
    if the statement contradicts the claims of the writer
    NOT GIVEN
     if it is impossible to say what the writer thinks about this 
     
    21
    Power companies have given Diels enough money to develop his laser. 
    22
    Obtaining money to improve the lasers will depend on tests in real storms. 
    23
    Weather forecasters are intensely interested in Diels’s system. 
     
     
     
     
     
     
     
     


    70 
    READING PASSAGE 4 
    HOW DOES THE BIOLOGICAL CLOCK TICK? 
    A
    Our life span is restricted. Everyone accepts this as ‘biologically’ obvious. ‘Nothing lives for ever!’ 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 (‘death’ 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 comparable? 
    B
    Our ‘dead’ products are ‘static’, closed systems. It is always the basic material which constitutes the object and 
    which, in the natural course of things, is worn down and becomes ‘older’. 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 become 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 thousand years, as with mammoth trees. 
    E
    If a life span is a genetically determined biological characteristic, it is logically necessary to propose 
    the existence of an internal clock, which in some way measures and controls the ageing process and which 
    finally determines death as the last step in a fixed programme. Like the life span, the metabolic rate has for 
    different organisms a fixed mathematical relationship to the body mass. In comparison to the life span this 
    relationship is ‘inverted’: the larger the organism the lower its metabolic rate. Again this relationship 
    is valid not only for birds, but also, similarly on average within the systematic unit, for all other 
    organisms (plants, animals, unicellular organisms). 
    F
    Animals which behave ‘frugally’ with energy become particularly old, for example, crocodiles and tortoises. 
    Parrots and birds of prey are often held chained up. Thus they are not able to ‘experience life’ and so 
    they attain a high life span in captivity. Animals which save energy by hibernation or lethargy (e.g. bats or 
    hedgehogs) live much longer than those which are always active. The metabolic rate of mice can be reduced by 
    a very low consumption of food (hunger diet). They then may live twice as long as their well fed 


    71 
    comrades. Women become distinctly (about 10 per cent) older than men. If you examine the metabolic rates of 
    the two sexes you establish that the higher male metabolic rate roughly accounts for the lower male life span. 
    That means that they live life ‘energetically’ - more intensively, but not for as long. 
    G
    It follows from the above that sparing use of energy reserves should tend to extend life. Extreme high 
    performance sports may lead to optimal cardiovascular performance, but they quite certainly do not prolong 
    life. Relaxation lowers metabolic rate, as does adequate sleep and in general an equable and balanced 
    personality. Each of us can develop his or her own ‘energy saving programme’ with a little self-observation, 
    critical self-control and, above all, logical consistency. Experience will show that to live in this way not only 
    increases the life span but is also very healthy. This final aspect should not be forgotten. 

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