I am sorry, I don't completely understand, could you give me more infromation so that I can help.
Pretty sure it’s either a or c
The answer is *Which had undergone a complete makeover.* Adjective clauses identify the word it's modifying.
Answer:
D
Explanation:
Limestone caves are formed within the rocks that are made up of limestone. A peculiar fact about limestone is that, it cannot be dissolved in water, except rainwater. This is because rainwater absorbs carbon dioxide and thus becomes acidic. Rainwater therefore dissolves calcium carbonate and turns it into a calcium bicarbonate solution.
