Question

This type of fossil is the result of when the water moves the original bones and tissues of the organism. This leaves just an impression in the sediment. Minerals can then recreate the original shape of the organism.Preserved fossilPermineralizationNatural castTrace fossils

Answer 1

Thre are several types of fossils depending on how they formed and what they represent:

• Mold fossils:, An impression of the organisms in the substrate

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• Cast fossils:, A mineral copy of the organisms, formed when a mold is filled

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• Trace fossils (ichnofossils):, We observe evidence of the organisms' activity, such as nests, footprints, gastroliths, etc.

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• True form fossils: ,Fossils representing the organism.

In this example they are talking of mold fossils and cast fossils, so "natural cast" would be the right answer.