erosion all the natural processes that wear away earth and rock.

evidence the data used to draw a conclusion

excavation the process of finding something by digging for it

extinct no longer living on the earth; dying out

fossils the hardened remains of animals or plants of prehistoric times

geologists scientist who study the earth’s crust and its rocks

Hypotheses (inferences) scientific suggestions, based on what is known so far

paleontologist a scientist who studies prehistoric life

specimens samples taken for scientific study

theory -a widely held scientific explanation that is based on evidence but cannot be stated as fact

emerged began to appear or develop

prey an animal hunted or caught by other animals for food

marrow the soft material inside bones that is the source of red and many white blood cells

embryos animals in their earliest stages of growth, before birth

agility the ability to move quickly and easily