I would Say C. Water I’m not sure but that’s my best guess
I'm pretty sure the answer is B, but don't hate me if I'm wrong
Answer: D. It can melt to a depth of a few meters in summer, then refreeze in winter.
Explanation:
Permafrost is ground which remains frozen for two or more years. Permafrost consists of soil, rock and sand fused together by ice. Mostly found in areas in high altitude, the Arctic, Antarctica, it is common in periglacial environments where temperatures are below freezing
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The topmost layer of permafrost can melt in summer and refreeze in winter. This thawing and refreezing produces a ground pattern called columnar joints similar to the one formed when molten lava cools.
Answer: B.
Explanation:
I believe it is B. because the population hasn't had much of an increase and in the next 50 years I think it will still be the same from now till 50 years.