Submit your answers to these questions: How is your mold fossil like the shell?
How is your mold fossil different from the shell?
Describe what happens when a cast fossil forms.

The rare fossil casts form when a mold fills with material, such as sediments or soluble minerals, and creates a replica of the original organism. A cast can be compared to putting Jell-o into a mold and letting it set; the removed form is a cast of the mold.

Although mold fossils and cast fossils seem the same, they're different. While the mold forms the outside of an object, the cast is formed from within the mold. A good way to understand the difference is to compare ice to the tray holding the ice. In other words, the tray is the mold and the ice is the cast

Explanation:The rare fossil casts form when a mold fills with material, such as sediments or soluble minerals, and creates a replica of the original organism. A cast can be compared to putting Jell-o into a mold and letting it set; the removed form is a cast of the mold.