A fossil is the preserved remains or traces of a once-living organism, often found in rocks.

A cast fossil is a type of fossil that forms when a mold of an organism is filled with minerals, creating a replica of the original organism.

Fossils can tell us about the history of life on Earth, how organisms have changed over time, and the environments they lived in.

It means that the fossil is a cast, which is a direct replica of the body part of the once-living thing.

Some fossils are more common because the organisms were abundant, lived in environments that favored fossilization, or existed for a long time.

A carnivore is an animal that primarily eats other animals.

We can infer that turtles have not changed much over millions of years.

We find many fern fossils because ferns have changed little over time and were abundant in many environments.

It means that the area was once covered by water a long time ago.

A footprint fossil is a trace fossil that shows the impression left by an animal's foot.