The document discusses several theories about what caused the extinction of dinosaurs. The main theory is that an asteroid impact killed all the dinosaurs. Other theories include starvation due to lack of plant food for herbivores, volcanic eruptions, climate change, and diseases from poisonous plants or animals eating eggs. The document also describes how some dinosaurs, such as ankylosaurs and stegosaurs, were armored for protection, while others like raptors had speed to evade predators.