Approximately what percentage of the world's population relies on water from karst areas?

The correct answer highlights that approximately 25% of the world's population depends on water sourced from karst areas. This is significant because karst landscapes are characterized by unique geological formations, which include features like caves, sinkholes, and underground rivers, resulting from the dissolution of soluble rocks such as limestone. These areas often have a high level of aquifer development, making them crucial sources of freshwater.

Understanding the reliance on karst water is essential for various reasons, including water supply, ecosystem health, and vulnerability to pollution and climate impacts. Recognizing that a quarter of the global population depends on these systems emphasizes the importance of protecting these environments to ensure sustainable water resources for future generations.

In this context, the other percentages do not accurately reflect how much of the global population relies on karst water. Fewer populations rely on karst water at the lower percentages, and although karst areas are extensive, the number of people depending on them is significant but doesn't reach the higher percentages listed.