Theme 2: What Really Happened?Selection 3: Hundreds of dinosaurs once died in a small area in New Mexico. As you read about what might have happened, monitor your understanding. Clarify difficult parts by rereading or reading ahead.

asteroids: small often irregularly shaped bodies that orbit the sun

embryos: animals in their earliest stages of growth, before they are born

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

excavation: the process of finding something by digging it up

extinct: no longer living on earth; having died out; gone forever

prehistoric: time before history was recorded in writing.

fossils: the hardened skeletons or other remains of creatures of prehistoric times

geologist: scientists who study the earth’s crust and the rocks it is made of

paleontologist: a scientist who studies prehistoric life

specimens: samples taken for scientific study