Any preserved remains, impression, or trace of any once-living thing.

Determining the age of rocks from the decay of their radioactive elements.

The loss of many species within a relatively short period of time.

The movement of earth’s land masses relative to one another.

The amount of time it takes for half of the material of an radioactive isotope to decay.

A stationary point on the Earth's surface that has experienced active volcanism for a long period of time.

Plate tectonic boundaries where two plates converge, and one plate is pushed beneath the other.

An underwater mountain system formed by a divergent tectonic plate boundary.

Determining the approximate age of a rock or fossil based off its location/depth in the ground.

The preserved remains of an organism that is used to date the rocks and fossils around it.