Biology - Evolution Question with Solution | TestHub

Fossils are preserved remains or traces of ancient organisms.

A mould is formed when an organism is buried in sediment and then decays, leaving a hollow cavity that retains the exact shape of the organism.

When mineral-rich water seeps into this cavity (mould) and the minerals precipitate and harden, they form a solid replica of the original organism. This type of fossil is known as a cast.

Therefore, the deposition of hardened pieces of mineral matter in the cavities of moulds forms a cast.

Answer: cast