Fossils

_______________ are the preserved evidence of organisms that used to be alive.

• Decay

• Bacteria

• Fossils

• Amber

Fossils that come from the remains of an organism, such as shells, bones, or teeth are called __________ fossils.

• body

• trace

• sedimentary

• mineral

Almost all fossils are preserved in _______________________ rocks.

• igneous

• metamorphic

• volcanic

• sedimentary

Quickly settling sediment is an ideal environment for fossil formation and preservation, because rapid burial protects dead organisms from ____________________________.

• silt and clay

• decay and scavengers

• mold and minerals

• carbon and tar

A whole organism can be preserved in ________________________.

• ice, amber or tar

• mold, minerals, or burrows

• silt, clay, or loam

• shell, footprints, or film

An organism can decay and leave a detailed imprint of itself inside the rock called a mold. The mold can then be filled with minerals which form a copy of the organism called a _________.

• decay

• trace

• carbon

• cast

In a carbonized fossil, the carbon in an organism’s body leaves a thin ________ in rock, which preserves the shape of the organism.

• footprint

• film

• imprint

• shell

With __________________ fossils, a bone or shell is partly or completely replaced with minerals. Only some of the original material remains, or none at all, but the shape is identical.

• replacement

• replica

• preserved

• carbonized

Fossils made from impressions of footprints, burrows, and other shapes left by the movement of organisms are called ________________ fossils.

• common

• cast

• mold

• trace

Fossils are rarely complete or provide a complete record of what an organism looked like because soft parts, such as organs, decay too quickly to become fossilized. Most fossils are evidence of the hard parts of organisms, such as _________________________________.

• footprints, burrows, or other shapes

• silt, clay or sediment

• bones, teeth, or shells.

• organs, muscles, or skin