How did the dinosaurs go extinct?
During the extinction of the dinosaurs there was a large meteorite impact along with massive volcanic eruptions in the Deccan traps. It seems likely that the combination of these two things killed the dinosaurs. Whether one of these things could have done it without the other is still up for debate - to the best of my knowledge, we don't know. It was almost certainly one of or both of those event though. I don't think there are any serious alternatives.