Zhucheng is known as the "hometown of dinosaurs" because its paleogeography and paleoenvironment provide conditions for dinosaurs to inhabit and survive.

During the 654.38+600 million years when dinosaurs ruled the world, the climate of the earth has been relatively stable. At that time, the climate was warm, the rain was abundant, the vegetation was lush, gymnosperms were lush, algae were abundant, and there was no strong crustal movement. The age of dinosaurs was once in its heyday. The Mesozoic in which dinosaurs lived had a high carbon dioxide content in the atmosphere, indicating that dinosaurs were very adapted to the atmospheric environment with high carbon dioxide concentration. But then, at the end of Cretaceous, the atmospheric environment changed greatly. The content of carbon dioxide decreased and the content of oxygen increased. This unfavorable environment may be reflected in two aspects: 1. Dinosaurs are uncomfortable, they are easy to get sick in a new environment, and diseases will spread like a plague. 2. The new atmospheric environment is more suitable for the survival of mammals, and mammals have become more advanced and adaptable competitors. Under the action of these two factors,

So choose: D.