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  3. The present economy remains dependent on a massive inward flow of natural resources that includes vast amounts of non-ren

The present economy remains dependent on a massive inward flow of natural resources that includes vast amounts of non-ren

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问题             The present economy remains dependent on a massive inward flow of
       natural resources that includes vast amounts of non-renewable resources,
       followed by a reverse flow of economically spent matter back to the ecosphere.
Line     Chemical sustainability problems are determined largely by these economy-
(5)      ecosphere material flows which current chemistry education essentially ignores,
       such that it has become imperative for chemists to develop the technological
       dimension of a sustainable civilization.  Chemistry teachers should better
       emphasize the effect of compositions, outcomes, and economics of chemical
       processes on both human health and the ecosphere. There is one overarching
(10)     scientific reason why chemical technology pollutes: chemists developing new
       processes strive principally to achieve reactions through relatively simple
       reagent designs by employing almost the entire periodic table to attain diverse
       reactivity, while by contrast nature accomplishes a huge range of selective
       biochemical processes through a reagent design much more elaborate than the
(15)     aforementioned synthetic ones. Electric eels can store charge via concentration
       gradients of biochemically common alkali metal ions across the membranes of
       electroplaque cells, while synthetically-designed batteries used for storing
       charges must make use of elements such as lead and cadmium. Given this
       strategic difference, manmade technologies often distribute throughout the
(20)     environment persistent pollutants that are toxic because they contain elements
       that are used sparingly or not at all in biochemistry.
           Imagine all of Earth’s chemistry as a mail sorter’s wall of letter slots in a
       post office, with the network of compartments extending toward infinity, each
       of which representing a separate chemistry so that, for example, thousands of
(25)     compartments are associated with stratospheric chemistry or with a human cell.
       An environmentally mobile persistent pollutant can move from compartment to
       compartment, sampling a large number and finding those it can perturb, and
       while many of these perturbations may be inconsequential, others can cause
       unforeseen catastrophes, such as ozone holes or endocrine disruption in the
(30)     human body. Most compartments remain unidentified, furthermore, giving
       ample reason for scientific humility when considering the safety of persistent
       mobile compounds.
           There are several obstacles to overcome in achieving a sustainable
       chemistry free of these mobile pollutants, the first being that of incorporating
(35)     environmental considerations into decisions concerning the reactions and
       technologies to be developed in the laboratory. It is equally critical that
       chemistry that is not really green does not get sold as such, and that the public
       is not misled with false or insufficient safety information. And since many
       chemical sustainability goals such as those associated with solar energy
(40)     conversion call for ambitious, highly creative research approaches, short-term
       and myopic thinking must be avoided-after all, chemistry exerts a near
       boundless influence on human action and is thus inextricably intertwined with ethics.
The author refers to lead and cadmium (line 18) in order to show
选项 A、elements commonly used in biochemistry
B、elements that produce only a single desired product through their reaction
C、elements more common in nature than alkali metals
D、elements less efficient at producing electrical charges than alkali metals
E、elements which are sometimes used in simple reagent design
答案E
解析
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