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In this task, you're given an article and an answer. Your task is to generate the question for the answer based on the given article.
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Article: Wood Buffalo National Park Wood Buffalo National Park is Canada's largest national park and one of the largest in the world. Established in 1922 to protect the last remaining herds of bison in northern Canada, it now protects an outstanding example of Canada's Northern Boreal Plains. The park was designated a World Heritage Site in 1983. Phone: (780) 697-3662 E-mail: wbnp.info@pc.gc.ca Banff National Park of Canada Banff's rich history dates back to 1885, when three railway workers stumbled upon hot mineral springs surfacing from deep within the mountains. This discovery led to the establishment of Banff National Park, and marked the beginning of Canada's national park system. Spanning 6,641 meadows and rivers, Banff National Park is one of the world's premier destination spots. Phone: (403)762-1550 E-mail: banff.vrc@pc.gc.ca St. Lawrence Islands National Park of Canada Conceived in the 1870s, St. Lawrence Islands is one of Canada's oldest national parks. Located in the scenic 1,000 Islands tourist area, this tiny jewel has a rich and complex natural human history. Centuries ago, aboriginal peoples referred to it as the "Garden of the Great Spirit". Today, 24 scenic islands, along with a mainland area at Mallory town Landing, are included in the park. Phone: (613) 923-5261 E-mail: ont. sli@pc.gc.ca Grasslands National Park of Canada It was here Sitting Bull took refuge after the Battle of Little Big Horn in 1876. Grasslands National Park is the first national park of Canada to preserve a portion of the mixed prairie grasslands. This magical land of diversity, beauty and history is divided into two blocks. The East Block contains the Killdeer Badlands and the Wood Mountain Uplands, and the West Block preserves the Frenchman River Valley and the dissected plateaus, coulees and famous 70 Mile Butte. Phone: (306) 298-2257 E-mail: grasslands. info@pc.gc.ca
Answer: Because hot mineral springs were found in Banff.
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Why was Banff National Park built?

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Article: TransLink is urging customers to avoid non-essential travel today and to stay home where possible in the difficult weather conditions. TransLink chief executive officer Peter Strachan said bus and train services were continuing to run where possible, however all CityCat and CityFerry services had been cancelled until further notice. "These are extremely difficult conditions for South East Queensland---we are running essential services where possible but safety remains to be the most important," Mr Strachan said. "Severe weather and associated flooding has impacted on all modes of public transport, with bus, ferry and train services all impacted to varying degrees. "If you are planning to use public transport at anytime over the next few days, then I would recommend you check that your intended service is still running." Service disruptions for today include: l City network trains running hourly on all lines. l Bus diversions, delays and cancellations in some regions, particularly across Brisbane, Ipswich and the Sunshine Coast. l CityCat and CityFerry services cancelled. Queensland Rail Chief Executive Officer Paul Scurrah said rising waterways had closed some train lines, and road closures and damage to property throughout the South-East had contributed to a shortage of available rail employees. "We intend to run trains hourly on all lines, similar to the timetable we operate on Christmas Day. We will also be looking to run other additional services to meet demand as required. At this stage we will run services stopping at all stations which will depart at the same time on the hour, however, this is all subject to the weather conditions and the availability of traincrew." Mr Scurrah encouraged all customers to visit the Translink website for specific departure times for their station, and asked for patience in the event of delays. "Queensland Rail appreciates that reduced services may cause disruptions but it is simply unavoidable. We have a dedicated and experienced team monitoring the situation around the clock and will be working to reopen the network as soon as practicably possible," Mr Scurrah said. The latest service disruption information is available on the TransLink website www.translink.com.au.
Answer: Plane.
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Which means of transport is NOT available during the special period?

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Article: As the nights get lounger, those who suffer from the winter blues will be planning ways to escape to the sunshine. But there may be a much simpler way of cheering yourself up... simply shining a bright light into your ear canal. Up to one in four Britons suffer from seasonal affective disorder, with seven per cent of the population having full-blown SAD. It is caused by the brain not receiving enough daylight which is needed to trigger serotonin , a hormone that regulates mood. Symptoms range from mild lethargy to depression and insomnia, but a cure might be in sight. Two clinical trials, run by Valkee - who make a device that can shine light into your ear - and the University of Oulu in Finland, have found that carefully targeted light can help prevent the condition. Juuso Nissila, Valkee's co-founder and chief scientist said: "We presented earlier that the human brain is sensitive to light". "These two clinical trials demonstrate that channeling bright light via ear canal into brain's photosensitive areas effectively prevents and treats seasonal affective disorder." The University of Oulu reported that in their first study, 92 per cent of the patients with seasonal affective disorder achieved full remission after a month of daily eight-to-12 minute doses of light from the Valkee. Time Takala, chief physician at the Oulu Deaconess Institute said: "These two trials show that bright light channeled into the brain via ear canal is an important future method to treat seasonal affective disorder." Valkee launched its bright light headset in August 2010. It is classed as a medical device under EU regulations. The device channels bright light direct to the brain via the ear canal to prevent and cure depression, mood swings and even circadian-rhythm disorders such as jet lag. It costs PS185 and looks like an iPod - only the earphones emit light rather than sound.
Answer: Approximately a quarter.
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How many Britons suffer from seasonal affective disorder?