Assertion: mammoth's remain | /r/HasProperty | discovered in polar regions
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text: When their remains were first discovered in the polar regions, therefore, it was thought that at one time the polar regions had been very warm, with plenty of vegetation, and that owing to the gradual change of the earth's axis, the area which was once hot had gradually been brought into positions where it grew colder until at last the mammoth and mastodon were frozen out.