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  3. Although Consumers Union concedes that " no confirmed cases of harm to humans from manufactured nanoparticles have been reported

Although Consumers Union concedes that " no confirmed cases of harm to humans from manufactured nanoparticles have been reported

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问题     Although Consumers Union concedes that " no confirmed cases of harm to humans from manufactured nanoparticles have been reported", it adds that "there is cause for concern based on several worrisome findings from the limited laboratory and animal research so far. " It worries that particles that are nontoxic at normal sizes may become toxic when nanosized; that these nanoparticles, which are already present in cosmetics and food, can more easily "enter the body and its vital organs, including the brain", than normal particles; and that nanomaterials will linger longer in the environment. All of this really comes down to pointing out that some particles are smaller than others. Size is not a reliable indicator of potential harm to human beings, and nature itself is filled with nanoparticles. But the default assumption of danger from the new is palpable.
    Anti-nanotech sentiment has not been restricted to Consumers Union ’ s relatively short list of concerns. In France, groups of hundreds of protesters have rallied against even such benign manifestations of the technology as the carbon nanotubules that allow Parkinson’s sufferers to stop tremors by directing medicine to their own brains. In England members of a group called THRONG(The Heavenly Righteous Opposed to Nanotech Greed)have disrupted nanotech business conferences dressed as angels. In 2005 naked protesters appeared in front of an Eddie Bauer store in Chicago to condemn one of the more visible uses of nanotech: stain-resistant pants.
    These nanopants employ billions of tiny whiskers to create a layer of air above the rest of the fabric, causing liquids to roll off easily. It’s not quite what Kurzweil and Crichton had in mind, nor is it "little robots in your pants", as CNN put it. But nanotechnology arguably embraces any item that incorporates engineering at the molecular level, including mundane products like this one.
    Just as the nano label can be broadly applied to products for branding and attention-grabbing purposes, so too can critics use the label to condemn barely related developments by linking them to the(still hypothetical)problems of nanopollution and gray goo. But there’s a danger in thinking of nanotech only in god-or-goo terms. People at both extremes of the controversy fail to appreciate the humble, incremental, yet encouraging progress that nanotech researchers are making. And focusing on dramatic visions of nanotech heaven or hell may foster restrictions that delay or block innovations that can extend and improve our lives.
What worries Consumers Union is that nanoparticles ______.
选项 A、linger in environment and are omnipresent in nature
B、can enter the brain more easily than normal particles
C、become essential components of cosmetics and food
D、present in products may cause harm to human beings
答案D
解析 根据第一段第二句“It worries that particles that are nontoxic at normal sizes may become toxicwhen nanosized；…”，D应为答案。
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