GRE Reading Comprehension
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Source: NO2
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.
The author's contention about the importance of bacteria and fungi in the production of energy for life processes would be most clearly strengthened if which of the following were found to be true?
- A Both aerobes and anaerobes provide sources of energy through the decomposition of organic material.
- B Most compounds containing carbon are unavailable as energy sources except to some bacteria and fungi.
- C Bacteria and fungi break down inert material in ways that do not involve oxidation.
- D Many compounds remain inert, even in the presence of bacteria and fungi.
- E Bacteria and fungi assist in the synthesis of many organic compounds.