Why is groundwater pollution considered difficult to clean up? A. Because it is always visible on the surface.
B. Because it evaporates quickly.
C. Because it is located deep underground and moves slowly.
D. Because it is not affected by human activities.
The correct answer is C. Because it is located deep underground and moves slowly.
Groundwater pollution is particularly challenging to clean up because contaminants can spread slowly through aquifers, making it difficult to locate and remove them. Additionally, the depth and the complex geological formations can hinder access and remediation efforts. Groundwater often serves as a crucial source of drinking water, so its protection is vital.