Final answer:
The preservation of soft tissue commonly takes the form of option d) carbonization, where organic matter is preserved as a thin film of carbon.
Step-by-step explanation:
The preservation of soft tissue commonly takes the form of option d) carbonization. Carbonization is a type of fossil preservation where the organism is preserved as a residual thin film of carbon. This occurs under conditions where the organism is rapidly buried in an oxygen-free, low-energy sedimentary environment, which prevents bacterial decay. Leaves, fish, and graptolites are commonly preserved this way. Unlike permineralization, which is more common for porous tissues like bone and wood, or replacement, where the original material is substituted molecule-by-molecule by a secondary mineral, carbonization preserves soft tissue by leaving behind a carbon residue as the original organic matter decomposes.