remains of an organism preserved by the geologic process

a fossil used to date times, used with animals that lived a short time

a core sample typically taken from the polar ice caps 

determining if an fossil is younger or older

measuring the age of an event or object

undisturbed sedimentary rock, younger layers of rock are above older ones 

a theory that the earths crust is divided in to parts or tectonic plates

movement of the earths continents over geological time