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发布时间：2006-06-22 13:25     点击：

    (B) The effects of technological development cannot be controlled.

    (C) Some technological developments are beneficial.

    (D) The current states of technological development results in a good allocation of resources.

    (E) Applications of technological development are criminally destructive.

    The whole biosphere, like the individual organisms that live inside it, exists in a chemically dynamic states. In this homeostatic system, a great number of organic compounds are synthesized, transformed, and decomposed continuously; together, these processes constitute the major parts of the carbon cycle. For the smooth operation of this cycle, degradation is just as important as synthesis, the green plants produce great quantities of polymers, such as cellulose, and innumerable other compounds like alkaloids, terpenes, and fiavonoids, that green plants cannot use as sources of energy during respiration. The release of the carbon in these compounds for recycling depends almost entirely on the action of both aerobic and anaerobic bacteria and certain types of fungi. Some bacteria and fungi possess the unique and extremely important biochemical asset of being able to catalyze the oxidation of numerous inert products, thereby initiating reaction sequences that produce carbon dioxide and so return much carbon to a form that actively enters into life cycles once again.

    25. The passage contains information that would answer which of the following questions about the carbon cycle?

    Ⅰ What are some of the compounds that are broken down in the carbon cycle?

    Ⅱ Why are some compounds that are involved in the carbon cycle less reactive than others?

    Ⅲ What role do bacteria and fungi play in the carbon cycle?

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