the trace or remains of an organism that lived a loooong time ago, often preserved in sediment

• half-life
• fossil
• geologic time-scale
• evolution

this type of fossil is a mark or cavity made in sediment in the shape of a shell or other body

• cast
• trace
• petrified
• mold

this type of fossil is a mold filled with sediment that creates a solid copy of an organism

• mold
• petrified
• cast
• trace

this type of fossil is created when an organism's tissue is replaced by minerals

• cast
• mold
• amber
• petrified

this type of fossil is created during a process that preserved the delicate parts of plant leaves and insects

• amber
• petrified
• carbon film
• trace

this type of fossil provides evidence of the activities of ancient organisms; examples include marks left by footprints or tails

• mold
• carbon film
• trace
• cast

this material does an excellent job of preserving insect remains

• cast
• amber
• mold
• carbon film

a scientist who studies fossils

• geologist
• biologist
• paleontologist
• chemist

provides evidence about the history of life and past environments on earth, and how life has changed over time

• relative dating
• fossil record
• unconformities

the age of a rock compared to the ages of other rocks

• absolute age
• relative age