How were the lechuguilla caves formed?

This is a very good question, so I'm going to thank you for asking it in the first place. I would like to first tell you one amazing thing about the Lechuguilla caves were that they weren't formed like other average caves, up to down, when acidic water drips, and forms caves below us. The story of Lechuguilla was that oil from reservoirs not very far away under ground, and a chemical compound by the name of Hydrogen Sulfide gas piled up in there, and the culmination of the molecules underground, it created, well, a very, very strong acid. This is known as sulfuric acid. What the sulfuric acid did was pound through layers of the limestone existing underground. And what this did was form the Lechuguilla caves. And like at the beginning, the unique thing about the Lechuguilla was that this process made it form bottom to up, instead of top to bottom. 

343^x = 49^4-xx = 4-xx+x=42x = 4x = 4/2x = 2therefore x = 2

Your answer is d. silli hope this ! : ) i left an explanation down below if you need it: a sill forms when hot magma squeezes between layers of rock to form a hardened sheet of rock. a sill is basically a tabular sheet intrusion between old layers of sedimentary rock, volcanic beds, or in the direction of foliation inherent in metamorphic rock. the word sill means a concordant intrusive sheet.