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Permafrost and the Mountains

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Multiple Choice

What is permafrost?

  1. Permafrost is a layer of soil that remains frozen for two or more consecutive years.
  2. Permafrost is a layer of soil that remains frozen for at least one year.
  3. Permafrost is a layer of soil that remains frozen for at least three consecutive years.
  4. Permafrost is a layer of soil that remains frozen for at least four consecutive years.
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