首页
登录
职称英语
Natural flavorings and fragrances are often costly and limited in supply. Fo
Natural flavorings and fragrances are often costly and limited in supply. Fo
游客
2024-01-02
29
管理
问题
Natural flavorings and fragrances are often costly and limited in supply. For example, the vital ingredient in a rose fragrance is extracted from natural rose oil at a cost of thousands of dollars a pound; an identical synthetic substance can be made for 1% of this cost. Since the early twentieth century, success in reproducing these substances has created a new industry that today produces hundreds of artificial flavors and fragrances.
Some natural fragrances are easily synthesized; these include vanillin, the aromatic ingredient in vanilla, and benzaldehyde, the aromatic ingredient in wild cherries. Other fragrances, however, have dozens, even hundreds of components. Only recently has it been possible to separate and identit3, these ingredients by the use of gas chromatography and spectroscopy. Once the chemical identity is known, it is often possible to synthesize them. Nevertheless, some complex substances, such as the aroma of fresh coffee, have still not been duplicated satisfactorily.
Many of the chemical compounds making up these synthetics are identical to those found in nature, and are as harmless or harmful as the natural substances. New products must be tested for safety, and when used in food, must be approved by the U.S. Food and Drug Administration.
The availability of synthetic flavors and fragrances has made possible a large variety of products, from inexpensive beverages to perfumed soap to used cars with applied "new car odor." [br] From the passage we can learn that ______
选项
A、natural flavorings and fragrances are not quite dear
B、the limitation of natural flavorings and fragrances is clear
C、the supply of natural flavorings and fragrances is adequate to meet the demand
D、the cost of producing natural flavorings and fragrances is high
答案
D
解析
见第一段第一句:Natural flavorings and fragrances are often costly and limited in supply.因此选项D为答案。
转载请注明原文地址:https://tihaiku.com/zcyy/3326003.html
相关试题推荐
Manypartsoftheworldarelosingimportantnaturalresources,suchasfore
"GeothermalEnergy"Geothermalenergyisnaturalheatfromtheinteriorofth
"GeothermalEnergy"Geothermalenergyisnaturalheatfromtheinteriorofth
"GeothermalEnergy"Geothermalenergyisnaturalheatfromtheinteriorofth
"GeothermalEnergy"Geothermalenergyisnaturalheatfromtheinteriorofth
"GeothermalEnergy"Geothermalenergyisnaturalheatfromtheinteriorofth
"GeothermalEnergy"Geothermalenergyisnaturalheatfromtheinteriorofth
"GeothermalEnergy"Geothermalenergyisnaturalheatfromtheinteriorofth
"GeothermalEnergy"Geothermalenergyisnaturalheatfromtheinteriorofth
_____commonusageamongeconomists,theterm"naturalrate"ismisleading.A、Ith
随机试题
[originaltext]Whydowecry?Canyouimaginelifewithouttears?Notonlydo
(1)Innovation,theelixirofprogress,hasalwayscostpeopletheirjobs.I
党委将拟发展为()的发展对象,在一定范围和期限内公示,广泛听取党内外群众对公示对
晕厥的主穴为( )。A.水沟、百会、足三里、内关 B.内关、郄门、阴郄 C
(2014初) (一)资料 甲公司2013年12月31日简化的资产负
2012年第三季度全国100个城市的公共就业服务机构市场中,用人单位通过公共就业
班里要推选一位同学到校迎新晚会上表演。班长征询同学意见 ①小王说:小刘很有艺
关于中国古代名画,下列说法正确的是( )。A、《韩熙载夜宴图》创作于唐玄宗时期
医学伦理学是一门( )。A.研究道德的形成、本质及发展规律的科学 B.研究人
根据《标准施工招标文件》,关于资格审查委员会和评标委员会的说法,正确的有()A、
最新回复
(
0
)