AP BIOLOGY

Detailed explanation-1: -A mold forms when the hard part of an organism, such as a shell, is buried in sediment. Later, water carrying dissolved minerals may seep into the empty space of a mold. If the water deposits the minerals there, the result is a cast, a solid copy of the shape of an organism.

Detailed explanation-2: -An example of a cast fossil is a cast of a plant leaf or trilobite. Cast fossils are fossils that occur when an organism leaves a print in the mud, which is subsequently filled with sediment.

Detailed explanation-3: -Paleontologists deal with two basic kinds of fossils: body fossils and trace fossils.

Detailed explanation-4: -Types of Fossils-Body, Molecular, Trace & Carbon Fossil.

Detailed explanation-5: -Fossils are rarely the original unchanged remains of plants or animals. Fossil formation begins when an organism or part of an organism falls into soft sediment, such as mud. The organism or part then gets quickly buried by more sediment.