Why did some plants survive when dinosaurs became extinct?

No one really knows why some plants survived ,but the dinosaurs didn't. actually scientists think that a meteor didn't kill off the life on earth because the layer in the earth that's supposed to be full of dinosaur skeletons isn't, not at all. they think that something killed off the dinosaurs before the meteor came maybe volcanic eruptions or floods or a disease. No one can know for sure what killed the dinosaurs, but something did and we don't know what it was.