Here is the question :
WHAT ARE THESE PATAGONIAN CAVES MADE OUT OF?
Here is the option for the question :
And, the answer for the the question is :
[STC002792] Do you want to take a tour of the breathtaking Marble Caves in Chile Chico? After that, get yourself into a boat, and get out on Lake General Carrera and start paddling. The lonely lake is nourished by glacier runoff and extends into Argentina, while the Marble Caves are formed out of the Patagonian Andes. The lake crosses the border between the two countries. Over the course of more than 6,000 years, water erosion fashioned a marble-like beauty into the calcium carbonate that made up the cave walls. The colors you see on these walls are actually a reflection of the water below, which creates a kaleidoscopic effect, determined by the water levels and season, the best of which is between September and February. Because the caves can only be reached by boat, the first thing you should do is hop on a ferry, then sign up for a tour, and then be ready to be amazed.