Please explain the real reason for the extinction of dinosaurs.

(1) climate change theory: the late Cretaceous orogeny, climate upheaval, plants died, herbivorous dinosaurs died, and carnivorous dinosaurs were difficult to survive. In addition, the temperature dropped, and dinosaur eggs were difficult to hatch. And dinosaurs were warm-blooded animals, with no appearance and physiological function to keep out the cold ...

(2) constipation theory: herbivorous dinosaurs lived on plants such as cycads and ferns. Cause death.

(3) Alkaloid poisoning theory: Cycas, ferns and other plants later contained a large number of alkaloids, which were poisoned and died after eating too much ...

(4) Excessive oxygen theory: too many plants led to more oxygen in the air, which was close to modern times. It caused dinosaurs to die of anaerobic poisoning, and new life replaced dinosaurs ...

(5) Volcanic eruption theory. The ecological area around the volcano is destroyed, the blue sky is covered with volcanic ash, sunlight cannot enter the surface, plants die, and the temperature drops ......

(6) Ethnic aging theory: I don't know, I heard that the main reason is that dinosaurs were replaced by latecomers in the competition for survival ...

(7) Mammals compete: This means that mammals not only compete with dinosaurs for food, but also fear dinosaurs. Make it extinct.

(8) Geomagnetism vanishes: After the disappearance of geomagnetism, the earth received intensified external radiation, which had a great impact on the climate, making dinosaurs extinct ... (I don't know why geomagnetism disappears, other people's point of view)

(9) Planetary collision says: I don't need to introduce this

(1) Comet asteroid explosion says: swarm. Polluted the atmosphere and water sources, and some caused strong acid rain and poisonous rain, and dinosaurs were finally poisoned ...

(11) Intraspecific and interspecific competition of dinosaurs said that the activities of one creature often directly affected the survival of another, resulting in ecological imbalance and extinction. For example, carnivores with strong reproductive ability and developed brains appeared, and a large number of eggs laid by dinosaurs were stolen. As a result, the dinosaurs lost their children and grandchildren .......

(12) The extinction of dinosaur nuclear war said: I have read this kind of science fiction statement on the Internet, and I expressed my attitude in the question "Can dinosaurs talk like humans?" So let's go and see for ourselves.

(13) Deism: God wanted to breed smarter humans, but humans couldn't beat dinosaurs, so he went down to his old age.