首页
登录
职称英语
Researchers have made significant technological progress toward incr
Researchers have made significant technological progress toward incr
游客
2024-01-11
20
管理
问题
Researchers have made significant technological progress toward increasing the
amount of plastic that plants can grow and altering the composition of the plastic to
endow it with useful properties, but achieving both a useful
Line composition and high plastic content in the plant proves to be a formidable task.
(5) The chloroplasts of the leaves have so far shown themselves to be the best
location for producing plastic, but the chloroplast is the green organelle that
captures light, and high concentrations of plastic could thus inhibit
photosynthesis and reduce grain yields, and the challenges of separating the
plastic from the plant are awesome. Given sufficient time and funding,
(10) researchers could overcome these technical obstacles, but a greater concern has
made us question whether those solutions are worth pursuing. When calculating
all the energy and raw materials required for each step of growing a
biodegradable plastic made from plant sugar polyhydroxyalkanoate in plants, we
discovered that this approach would consume even more fossil resources than
(15) most petrochemical manufacturing routes.
In a recent study, scientists found that making one kilogram of
polyhydroxyalkanoate from genetically modified corn plants would require about
300 percent more energy than the 29 megajoules needed to manufacture an
equal amount of fossil fuel-based polyethylene (PE). Given this comparison, it
(20) is impossible to argue that plastic grown in corn and extracted with energy from
fossil fuels would conserve fossil resources. What is gained by substituting the
renewable resource for the finite one is lost, through a tremendous irony, in
the additional requirement for energy. Fueling this process requires 20 to 50
percent fewer fossil resources than does making plastics from petroleum, but it
(25) is still significantly more energy intensive than most petrochemical processes
are, even though developing alternative plant-sugar sources that require less
energy to process, such as wheat and beets, would eventually attenuate the use
of fossil fuels.
The energy necessary for producing plant-derived plastics gives rise to a
(30) second, perhaps even greater, environmental concern: fossil petroleum is the
primary resource for conventional plastic production, but making plastic from
plants depends mainly on coal and natural gas used to power the corn-farming
and corn-processing industries. Any of the plant-based methods, therefore,
involves switching from a less abundant fuel (petroleum) to a more abundant
(35) one (coal). Some experts argue that this switch is a step toward sustainability.
Missing in this logic, however, is the fact that all fossil fuels used to make
plastics from renewable raw materials (corn) must be burned to generate
energy, whereas the petrochemical processes incorporate a significant portion
of the fossil resource into the final product. Burning more fossil fuels
(40) exacerbates an established global climate problem by increasing emissions of
greenhouse gases, such as CO2, and SO2, which contribute to acid rain; thus
the environmental benefit of growing plastic in plants is overshadowed by
unjustifiable increases in energy consumption and gas emissions. [br] According to the passage, the new means of manufacturing plastic under consideration do not involve
选项
A、corn
B、plant sugar polyhydroxyalkanoate
C、petroleum
D、wheat
E、chloroplast plants
答案
C
解析
转载请注明原文地址:https://tihaiku.com/zcyy/3353054.html
相关试题推荐
______itisverylatenow,theresearchersarestillworkinginthelab.A、AsB、W
______itisverylatenow,theresearchersarestillworkinginthelab.A、AsB、
在他的帮助下,我的英语进步很大。Withhishelp,IhavemadegreatprogressinEnglish.
只要我们信任他,他一定会取得巨大进步。Aslongaswetrusthim,hewillmakegreatprogress.
Theprimarypurposeofthepassageisto______[br]Theresearchers’conclusion
Accordingtothepassage,by1935theskepticismofBlackworkerstowardunions
Accordingtothepassage,by1935theskepticismofBlackworkerstowardunions
Thepassageisprimarilyconcernedwith______[br]Theauthor’sattitudetoward
Australianresearchershavediscoveredelectroreceptors(sensoryorgansdesig
Australianresearchershavediscoveredelectroreceptors(sensoryorgansdesig
随机试题
I’mafraidyouhaveno______buttocomealongwithus.Oryoucouldn’tfindthe
Generally,womendon’tcontentthemselveswiththechores.Perhapsthereare
关于良心和义务之间关系下列说法不正确的是()。A.良心和道德是紧密联系在一起的
A.氢氰苷B.野樱苷C.麦芽糖酶D.苯甲醇E.苦杏仁苷原生苷
医疗机构、戒毒机构以开展戒毒治疗为目的A.可以使用美沙酮或者国家确定的其他用于戒
应用硫酸铜溶液救治的是A.阿片中毒B.磷化锌中毒C.氰化物中毒D.苯巴比妥中毒E
A.活血化瘀 B.消积化食 C.消食止泻 D.止血止泻 E.燥湿健脾生山
某市一家冰箱生产企业,2018年度取得主营业务收入7520万元,其他业务收人2
商业信用作为企业短期资金的一种来源,主要表现形式有( )。A.应付票据 B.
某在建工程施工过程中发生事故,事后统计,死亡5人,重伤32人,直接经济损失1.2
最新回复
(
0
)