You are presented with the question "what causes formations in caves" and the following answer choices: 
- Water expanding
 - calcite
 - oxygen
 - erosion
 - nitrogen
 - deposition
 - less water
 - carbon dioxide

Now knowing that stalactites are formed by deposition and inside the caves are some young stalactites and stalagmites in formation, choose the best answer.


 

      deposition   