Permafrost is a layer where soil temperature is always

Solution (By Examveda Team)

Permafrost is a layer where the soil temperature is always ≤ 0°C. It is defined as ground with a temperature that remains at or below freezing (0°C) for two or more consecutive years. It is a permanently frozen layer on or under the Earth’s surface. It consists of soil gravel and sand, usually bound together by ice.