Process:  - Animals and plants die in soft soil or mud - Sediment builds up over the remains - The remains decompose, leaving only trace amounts - The remaining parts over the years are replaced with mineral - A fossil is formed -   Perturbation hypothesis: suppose animal dying and sinking under water happens, how will it affect MORE fossils forming.  Does the supposed perturbation have an effect (direct or indirect) on the process?
The answer to this question is:
yes