The tundra and subarctic zones in Russia and the Near Abroad are permanently frozen to a depth of three meters. What is this permanently frozen layer called?

PERMAFROST LAYER

Explanation:

Permafrost layer is usually defined as the thick layer of soil that is mixed with the broken rock fragments and other sediments, and are covered by ice throughout the year. These are mostly found in the higher latitudinal region, where the thickness of these layers ranges from a few meters to tens and hundreds of meters. The melting of these layers in these regions leads to an increase in the sea level.

For example, the permafrost layers of tundra and subarctic zones in Russia and its nearby areas, which have a thickness of about three meters.

answer: option d.

explanation: