Permafrost refers to the fact that the ground in high latitudes which is permanently frozen - that is, which does not defreeze in the summer. It does not defreeze because it is isolated by soil - this is the correct answer - from the warmer air, so it is actually not in touch with the positive temperatures.
Plentiful harvests enabled people to specialize. Because not everyone had to be a farmer, some people could work with pottery while others could develop religions.
