Answer: Mountains
Explanation: Groundwater erodes rock beneath the ground surface, especially carbonate rock. Groundwater deposits material in caves to create stalactites, stalagmites, and columns. And we know that a sink whole is also known as a cenote, sink, sink-hole, swallet, swallow hole, or doline, is a depression or hole in the ground caused by some form of collapse of the surface layer. Most are caused by karst processes – the chemical dissolution of carbonate rocks or suffosion processes