Problem: Iron is usually found as iron ore on Earth, except for one deposit of native iron in Greenland, which was used by the Inuit people. Native copper, however, was found worldwide, along with silver, gold and platinum, which were also used to make tools, jewelry, and other objects since Neolithic times. Copper was the hardest of these metals, and the most widely distributed. It became one of the most important metals to the ancients. Eventually, humans learned to smelt metals such as copper and tin from ore, and, around 2500 BC, began alloying the two metals to form bronze, which is much harder than its ingredients. Tin was rare, however, being found mostly in Great Britain. In the Middle East, people began alloying copper with zinc to form brass. Ancient civilizations took into account the mixture and the various properties it produced, such as hardness, toughness and melting point, under various conditions of temperature and work hardening, developing much of the information contained in modern alloy phase diagrams. Arrowheads from the Chinese Qin dynasty (around 200 BC) were often constructed with a hard bronze-head, but a softer bronze-tang, combining the alloys to prevent both dulling and breaking during use.
What did humans began alloying around 2500 A.D.?
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Answer: unanswerable

Problem: Some of the theorists who advocate this "revisionist" critique imply that, because the "pure hunter-gatherer" disappeared not long after colonial (or even agricultural) contact began, nothing meaningful can be learned about prehistoric hunter-gatherers from studies of modern ones (Kelly, 24-29; see Wilmsen)
The "pure hunter-gatherer" appeared not long after what?
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Answer: unanswerable

Problem: Adult contemporary tends to have lush, soothing and highly polished qualities where emphasis on melody and harmonies is accentuated. It is usually melodic enough to get a listener's attention, and is inoffensive and pleasurable enough to work well as background music. Like most of pop music, its songs tend to be written in a basic format employing a versechorus structure.
What is the typical structure of an adult contemporary song?
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Answer:
versechorus structure