Problem: According to an October 1998 report by the United States Bureau of Land Management, approximately 65% of Alaska is owned and managed by the U.S. federal government as public lands, including a multitude of national forests, national parks, and national wildlife refuges. Of these, the Bureau of Land Management manages 87 million acres (35 million hectares), or 23.8% of the state. The Arctic National Wildlife Refuge is managed by the United States Fish and Wildlife Service. It is the world's largest wildlife refuge, comprising 16 million acres (6.5 million hectares).
What types of areas are managed by the federal government as public lands?
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Answer: national forests, national parks, and national wildlife refuges


Problem: Canada has the world's largest deposit of natural bitumen in the Athabasca oil sands and Canadian First Nations along the Athabasca River had long used it to waterproof their canoes. In 1719, a Cree Indian named Wa-Pa-Su brought a sample for trade to Henry Kelsey of the Hudson’s Bay Company, who was the first recorded European to see it. However, it wasn't until 1787 that fur trader and explorer Alexander MacKenzie saw the Athabasca oil sands and said, "At about 24 miles from the fork (of the Athabasca and Clearwater Rivers) are some bituminous fountains into which a pole of 20 feet long may be inserted without the least resistance."
For what  did Canadian natives use asphalt as a waterproofing material?
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Answer: canoes


Problem: There are seven state parks within the confines of New York City, including Clay Pit Ponds State Park Preserve, a natural area which includes extensive riding trails, and Riverbank State Park, a 28-acre (110,000 m2) facility that rises 69 feet (21 m) over the Hudson River.
How many meters is Riverbank State Park elevated above the Hudson River?
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Answer:
21