Which Rocks term is correctly associated with formation process: “commonly formed from calcium carbonate remains or precipitation”, and also with “reacts with dilute acid”?

Correct Answer: Option B — Limestone. Limestone is correct because it is commonly formed from calcium carbonate remains or precipitation. Limestone is also associated with reacts with dilute acid. A further identifying fact is that Limestone is reacts with dilute acid. Another useful fact is that Limestone is associated with a major raw material for cement. Why the other options are incorrect: Option A — Shale: It is formed from compacted mud and clay and is associated with splits into thin layers called fissility; those are the identifying facts of Shale. Option C — Marble: It is formed mainly by metamorphism of limestone and is associated with has interlocking calcite crystals; those are the identifying facts of Marble. Option D — Slate: It is formed mainly from shale under pressure and heat and is associated with splits into smooth thin sheets; those are the identifying facts of Slate. Exam Takeaway: Link Limestone with “commonly formed from calcium carbonate remains or precipitation” and “reacts with dilute acid” for quick revision.