GEOLOGY

Detailed explanation-1: -A fossilized impression made in the substrate; a negative image of the organism.

Detailed explanation-2: -mold fossils (a fossilized impression made in the substrate-a negative image of the organism) cast fossils (formed when a mold is filled in) trace fossils = ichnofossils (fossilized nests, gastroliths, burrows, footprints, etc.)

Detailed explanation-3: -Unlike cast fossils, mold fossils are hollow. Due to the way this type of fossil is formed, the resulting image is a negative image of the part of the organism’s body that made the impression. In other words, it is backwards. Common mold fossils include skin, leaves, teeth, claws and embryos.

Detailed explanation-4: -Sometimes when an animal dies and its body decays, it can leave an imprint in the sediment. If this imprint fills in with minerals from sediment and groundwater, it can harden to form a fossil. This fossil is called a cast fossil. The fossilized imprint is called a mold fossil.

Detailed explanation-5: -Body fossils include molds and casts.