Why do fossils form in sedimentary rock?

Answer: Layers bury and preserve remains

Layers bury and preserve remains ✓ — Correct! When organisms die in water or are buried quickly by sediment (mud, sand), soft parts decay but hard parts (bones, shells) remain. More sediment layers pile on top, creating pressure. Mineral-rich water seeps through, gradually replacing organic material with rock (permineralization). Millions of years later—fossil!

Volcanic heat preserves bones — Wrong. Volcanic heat destroys organic material rather than preserving it. Fossils form when organisms are buried in sediment and minerals gradually replace the original material over millions of years.

Organisms naturally turn to rock — Wrong. Organisms don't spontaneously turn to rock. Fossilization requires specific conditions: rapid burial, mineral-rich water, and millions of years for replacement.