What is the main characteristic of karst landscapes?

Karst landscapes are primarily characterized by their unique features that result from the chemical weathering process known as dissolution, particularly involving limestone and similar soluble rocks. The key aspect of a karst landscape is that water, often slightly acidic due to dissolved carbon dioxide, seeps into the ground and chemically reacts with minerals in the rock, especially calcite in limestone. Over long periods, this process creates distinctive topography that includes features such as sinkholes, caves, and underground drainage systems.

This process of dissolution leads to a variety of landforms that are typical of karst environments, setting them apart from other geographical formations. For instance, the formation of caves through the erosion and removal of limestone can create significant underground systems that can impact surface water flows and ecosystems. Thus, the correct answer captures the essence of what defines karst landscapes, emphasizing their development through the action of water as it shapes the geological features through dissolution.