Volcanic ash has occasionally formed molds of animals. this occurs when the ash covers the animal and -

Out of the following given choice;

F. replaces the animal's soft tissues.

G. enters the animal's body cavity.

H. hardens before the animal decays.

J. mineralizes the animal's bones.

The answer H. This can be caused by hot pyroclastic flows or falling volcanic ash from the atmosphere following a volcanic eruption. The ash buries animals and plants intact without moving them and without completely crushing or burning them. Over time excess silica dissolved in the water often replaces soft bone materials molecule by molecule, creating an almost indestructible fossil (like petrified wood) that lasts for millions of years