LIFE SCIENCE

Detailed explanation-1: -A layer of soil that freezes for more than 15 days per year is called “seasonally frozen ground.” A layer of soil that freezes between one and 15 days a year is called “intermittently frozen ground.” Permafrost is frozen for two years or more. Permafrost does not always form in one solid sheet.

Detailed explanation-2: -Permafrost plays an essential role in the Arctic ecosystem by making the ground watertight and maintaining the vast network of wetlands and lakes across the Arctic tundra that provide habitat for animals and plants.