Given the question: Answer the following question given this paragraph: As erosion by groundwater continues, the ceiling of a cave may collapse. The rock and soil above it sink into the ground. This forms a sinkhole on the surface. You can see an example of a sinkhole in Figure below . Some sinkholes are big enough to swallow vehicles and buildings. Q: What is formed when the ceiling of an underground cave collapses? Choices: - hill - groundwater - mountain - sinkhole A:
The answer is:
sinkhole