Here's a breakdown:

* Permafrost: Permafrost is a layer of soil or rock that has been frozen for at least two consecutive years. It's found in high-latitude and high-altitude regions like the Arctic and some mountainous areas.

* Active Layer: The active layer is the uppermost layer of soil that thaws during the summer months. It sits directly on top of the permafrost and can vary in depth depending on factors like climate, vegetation, and soil composition.

Think of it like this:

* Permafrost: The frozen foundation.

* Active Layer: The top layer that experiences seasonal thawing and freezing.

The active layer is important because it's where plants grow and biological processes occur. However, climate change is causing the active layer to thaw deeper and for longer periods, which can have significant impacts on ecosystems, infrastructure, and even global climate.