Other projections try to fill in those gaps. But that creates land and water that ___ ___ ___ ! Interrupted projections avoid this problem. Land and ocean ___ are ___. But those gaps can make interrupted projections ___ to understand.

Permafrost refers to  the part of ground (so not solid ice and not rocks) that are frozen over the whole year round. In the summer some uppermost layer might melt, but not the whole ground.

 Permafrost is found in the biome of tundra - and this is the correct answer (it can be found for example in Greenland)