Layers of particles of soil and rock that are carried by a river to a lake or ocean that settle to the bottom that, over millions of years, form layers and harden is called _______.

A fossil in which minerals replace all or part of an organism is called _______.

A hollow space in sediment in the shape of an organism or part of an organism is called _______.

A fossil that is a copy of an organism’s shape, formed when minerals seep into a mold called _______.

A technique used to determine which of two fossils is older is called _____.

A technique used to determine the actual age of fossils is called _____.

Unstable elements that decay, or break down, into different elements is called _____.

The time it takes for half of the atoms in a sample to decay is called _____.

The millions of fossils that scientists have collected is called ____.

A species that has no members of that species still alive is called ____.

One theory about how fast a species evolved billions of years ago that proposes that evolution occurs slowly but steadily is called ____.

A theory that says a species evolves during short periods of rapid change is called ____.

Similar structures that related species have inherited from a common ancestor is called ______.

A diagram that shows how scientists think different groups of organisms are related is called ______.