Given a question and a context passage, generate the answer having the word or phrase from the context passage. Here, the answer should be a shortest continous span from the passage.
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Question: Context: Modeled after US hot website.com, group buying websites are now popular in China. These websites use the power of group buying to get competitive discounts for a daily deal on some best stuff to do, see, eat and buy in the cities across China. Discounts are available within just one click. Zhao lei, a software engineer in Beijing, loves the one-hour lunch break at noon,as it is the best time for him to check "today's special" at his favorite group buying websites . Sometimes he searches for great deals at directory sites devoted to the new shopping space. Zhao spends around 800 yuan($117.65) on group buying every month, mostly to buy food coupons for eating at some nice restaurants and occasionally to find something fun to do. " I love group buying. In addition to the competitive discounts it offers, it helps me get something fun, exciting and new, and such surprises give me a reason to try something new," he said. When he finds a really good bargain, he will send the link to friends or colleagues through MSN,QQ, or e-mail, or share the information at some social networking websites. In doing so, he often gets a certain cut off the price. At some sites, buyers are invited to leave notes about what they want to buy and the website will consider it if similar applications reach a certain number. That is how Zuo got her digital camera after waiting for two months. "It is cool. I want to buy a new digitgal camera for my trip to Switzerland this winter, but I never expected such cheap prices!" Zuo said.
Question: What is the passage mainly about?

Answer: group buying

Question: Context: Even while in a deep sleep, people can still learn brand new information. Sleepers soak in new associations between smells and sounds, knowledge that lingers into the next waking day, researchers report online August 26 in Nature Neuroscience. The new study is the first to show that entirely new information can get into the sleeping mind, says Anat Arzi of the Weizmann Institute of Science in Israel. "The brain is not passive while you sleep. It's quite active. You can do quite a lot of things while you are asleep." But the results don't mean that Spanish vocabulary tapes now have a place on the nightstand. L, Researchers have tried but largely failed to find evidence that complicated information, such as new pairs of words, can make its way into the brain during sleep. Instead of trying to teach people something complicated like a new language, Arzi and her colleagues relied on the sense of smell and hearing. As anyone who has walked by a dumpster in July knows, smells can cause a nose-jerk reaction. Catching a bad smell automatically makes people inhale less, reducing the size of the inhale. But scent of fresh bread causes a long, deep inhale., rzi and her team took advantage of this reaction for their experiment. As people slept in the laboratory, the researchers delivered pleasant scent, such as shampoo. As this nice smell got into the sleepers' noses, the researchers played a particular music. Later, a disgusting smell, such as rotten fish or meat, was paired with a different music. Neither the smell nor the sound woke people up. After just four exposures to the smell-music pair during a single night, the sleepers started to automatically respond to the tones without the accompanying smells, taking in bigger breaths when the shampoo-associated tone played and smaller breaths when played the sound linked to the rotten fish smell. This new learned association lingered into the next waking day, too. Even though the sleepers had no idea they had been exposed to smells or sounds, their behavior proved that their brain had actually learned something during sleep. As before, the shampoo sound stimulated a long, deep inhale, while the rotten fish tone caused more shallow breaths.
Question: In which part of a website may this passage most likely appear?

Answer: science.

Question: Context: Among the movement disorders associated with acanthocytosis, McLeod syndrome (McKusick 314850) is the one that is best characterized on the molecular level. Its defining feature is low reactivity of Kell erythrocyte antigens. This is due to absence of membrane protein KX that forms a complex with the Kell protein. KX is coded for by the XK gene on the X-chromosome. We present six males (aged 29 to 60 years), with proven XK mutations, to discuss the chorea associated with McLeod syndrome. The movement disorder commonly develops in the fifth decade and is progressive. It affects the limbs, the trunk and the face. In addition to facial grimacing, involuntary vocalization can be present. In early stages there may only be some restlessness or slight involuntary distal movements of ankles and fingers. Lip-biting and facial tics seem more common in autosomal recessive choreoacanthocytosis linked to chromosome 9. This, together with the absence of dysphagia in McLeod syndrome, may help in differential diagnosis. Recent findings suggest a role for the endothelin system of the striatum in the pathogenesis of McLeod syndrome.
Question: Mutation of which gene is associated with McLeod syndrome?

Answer:
xk