Answer:
Option 4. Caves are formed by the actions of groundwater.
Explanation:
Caves are form from just two ingredients: rocks and water. When rocks such as limestone, gypsum or dolomite dissolute due to groundwater going through them the process beings. Groundwater is rain water that has perforated the soil. The acidic groundwater mixed with particles of organic material that comes from dead plants starts to eat through the rock and after several hundred years or even thousands of years, a cave is formed.
