Scientists find fossils of a wide variety of dinosaur species throughout Mesozoic rocks, which date from approximately 250 million to 65 million years ago. Above the Mesozoic rocks lie Cenozoic rocks, which date from approximately 65 million years ago to the present day. No dinosaur fossils exist in the overlying Cenozoic rocks. What is the most likely explanation for the lack of dinosaur fossils in Cenozoic rocks?
A. The dinosaurs' biological diversity increased in the Cenozoic Era.
B. Dinosaurs adapted in the Cenozoic Era so that their bodies could no longer be preserved as fossils.
C. There was a mass extinction of dinosaur species at the end of the Mesozoic Era.
D. There was a mass extinction of dinosaur species at the end of the Cenozoic Era.