Fact 1: Acavern is formed by carbonic acid in groundwater seeping through rock and dissolving limestone. Fact 2: When caves contain connecting rooms, they are called caverns. Given the two facts above, what is one element used to create caves?

Select from: A). sunlight B). heat energy C). Calcium carbonate D). hydrogen and oxygen E). calcite F). carbonic acid G). less water H). salinity
The answer is:
F).