Question

What happens to soft parts of organisms when cast fossils form?

They decay.
They petrify.
They form carbon films.
They become part of the fossil.

Answer 1

When cast fossils form, the soft parts of organisms typically **decay**. Cast fossils are formed when an organism is buried and eventually decomposes, leaving an impression or cavity in the sediment. This space can later be filled with minerals or sediments, creating a cast of the organism. While some soft tissues can sometimes leave behind carbon films or be preserved under specific conditions, in the context of cast fossil formation, decay is the primary process.