Earth's History - Test Review

A fossil is ____.

• any dead organism

• the preserved remains or traces of an organism

• a perfect copy of a rock

• an unusual type of rock

How do most fossils form?

• Living things die and their remains are buried by sediments

• The hard parts of an organism dry out in the air

• The soft parts of an organism change to stone

• Freezing preserves the remains of an organism

A fossil formed when minerals replace all or part of an organism is called a ____.

• mold

• petrified fossil

• cast

• trace fossil

____ can provide clues about the activities of ancient organisms.

• Trace fossils

• Remains preserved in amber

• Carbon films

• Molds and casts

The process by which all the different kinds of living things have changed over long periods of time is called ____.

• sedimentation

• replacement

• deposition

• evolution

A type of organism that no longer exists on Earth is said to be ____.

• fossilized

• sedimentary

• extinct

The relative age of a rock is ____.

• its age compared to the ages of other rocks

• less than the age of the fossils the rock contains

• the number of years since the rock formed

• its age based on how much carbon-14 the rock contains

The law of superposition states that, in horizontal layers of sedimentary rock, each layer is ____.

• younger than the layer above it and older than the layer below it

• neither older nor younger than the other layers

• older than the layer above it and younger than the layer below it

• always older than any vertical layers

The fossils of organisms that were widely distributed but only lived during a short period of time are called ____.

• trace fossils

• petrified fossils

• index fossils

• carbon film fossils

Radioactive decay occurs when atoms of an unstable element ____.

• become part of a fossil

• join with atoms of another element

• break down to form atoms of another element

• are exposed to chemical weathering