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问题 选择题

下列各物质中，不能发生水解反应的是（　　）

A．葡萄糖

B．纤维素

C．油脂

D．蛋白质

答案

选项中葡萄糖是单糖不能水解；纤维素是多糖在一定条件下水解最终生成为单糖；油脂在酸、碱等催化作用下水解生成甘油和高级脂肪酸；蛋白质一定条件下水解生成氨基酸；

故选A．

单项选择题

用1，2，3，4，5这五个数字组成没有重复数字的自然数，从小到大顺序排列：1，2，3，4，5，12，…，54321。其中，第206个数是（）。

A．313

B．12345

C．325

D．371
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单项选择题

She’s cute, no question. Symmetrical features, flawless skin, looks to be 22 years old—entering any meat-market bar, a woman lucky enough to have this face would turn enough heads to stir a breeze. But when Victor Johnston points and clicks, the face on his computer screen changes into a state of superheated, crystallized beauty. "You can see it. It’s just so extraordinary," says Johnston, a professor of biopsychology at New Mexico State University who sounds a little in love with his creation.
The transformation from pretty woman to knee-weakening babe is all the more amazing because the changes wrought by Johnston’s software are, objectively speaking, quite subtle. He created the original face by digitally averaging 16 randomly selected female Caucasian faces. The changing program then exaggerated the ways in which female faces differ from male faces, creating, in humanbeauty-science field, a "hyper-female". The eyes grew a bit larger, the nose narrowed slightly and the lips plumped. These are shifts of just a few millimeters, but experiments in this country and Scotland are suggesting that both males and females find "feminized" versions of averaged faces more beautiful.
Johnston hatched this little movie as part of his ongoing study into why human beings find some people attractive and others homely. He may not have any rock-solid answers yet, but he is far from alone in attempting to apply scientific inquiry to so ambiguous a subject. Around the world, researchers are marching into territory formerly staked out by poets and painters to uncover the underpinnings of human attractiveness.
The research results so far are surprising—and humbling. Numerous studies indicate that human beauty may not be simply in the eye of the beholder or an arbitrary cultural artifact. It may be ancient and universal, wrought through ages of evolution that rewarded reproductive winners and killed off losers. If beauty is not truth, it may be health and fertility: Halle Berry’s flawless skin may fascinate moviegoers because, at some deep level, it persuades us that she is parasite-free.
Human attractiveness research is a relatively young and certainly contentious field—the allure of hyper-females, for example, is still hotly debated—but those on its front lines agree on one point: We won’t conquer "looks-ism" until we understand its source. As psychologist Nancy Etcoff puts it: "The idea that beauty is unimportant or a cultural construct is the real beauty myth. We have to understand beauty, or we will always be enslaved by it. \

Paragraph 4 suggests that human beauty may be ______.

A．culturally different

B．a disease-free idol

C．individual-dependent

D．a world agreed value
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