How dinosaurs became extinct are the three most recognized possibilities

1. The asteroid hit the earth hypothesis: The asteroid hit the earth, causing a large amount of dust to be produced by the earth, which made the earth's atmosphere obscure the sky and the sun, and the animals at that time froze or starved to death. (The more common statement at present) 2. Volcanic eruption hypothesis:

At the end of the Cretaceous period, there was a volcanic eruption, and the violent volcanic activity sprayed a large amount of ash, sulfate, and carbon dioxide into the atmosphere, blocking the sunlight and cold climate, which caused the dinosaurs to extinct. 3. Climate change hypothesis: The Jurassic humid and hot, almost perennial temperature remained unchanged until the Cretaceous global natural environment deteriorated, the climate seasonality was obvious, the temperature difference between day and night became larger, and the warm and humid climate zone gradually shrank, resulting in the extinction of the dinosaurs.

There are also two hypotheses that are more credible: 1. Food poisoning or scarcity hypothesis: In the late Cretaceous period, plants were replaced, so that dinosaurs could not eliminate plant toxins in the process of changing food, resulting in their death.

At the same time, it is not excluded that the dinosaur population is less fertile due to food scarcity, so as to reduce population pressure 2. Ocean change hypothesis: Since the middle Cretaceous, the separation and drift of continental plates have accelerated significantly, the ocean circulation has become more complex, and the crustal movement has intensified, causing the sea to retreat and the temperature to rise, leading to the extinction of the dinosaurs.

1 Meteorite impact on the earth 2 Climate change Dinosaurs failed to adapt 3 ** The frequent occurrence of natural disasters such as volcanic eruptions.

1. Asteroid impact theory: 65 million years ago, an asteroid with a diameter of about 10 kilometers collided with the earth, and a large amount of dust was thrown into the atmosphere, causing the sunlight to be blocked within a few months, the earth was dark and cold, plants died, the food chain was interrupted, and many animals, including dinosaurs, were extinct.

2. Species struggle theory: Species struggle theory is an analytical hypothesis conducted by scientists on the extinction of dinosaurs.

3. At the end of the dinosaur era, the first small mammals appeared, which were rodent carnivores and probably fed on dinosaur eggs. Due to the lack of natural predators in this small animal, more and more, and eventually they ran out of dinosaur eggs. 4. Geomagnetic change said:

Modern biology proves that the death of certain organisms is related to magnetic fields. Organisms that are sensitive to magnetic fields can lead to extinction when the earth's magnetic field changes. It can be inferred that the extinction of the dinosaurs may be related to changes in the Earth's magnetic field.

5. Angiosperm poisoning theory: At the end of the dinosaur era, a large number of poisonous angiosperms appeared, and over time, dinosaurs died one after another due to chronic food poisoning.

6. Acid rain said: Acid rain said that at the end of the Cretaceous period, there may have been strong acid rain, so that the trace elements in the soil, including strontium, were dissolved, and the dinosaurs directly or indirectly ingested strontium through drinking water and food, resulting in acute or chronic poisoning, and the last batch died.

7. Disease theory: Among the dinosaur extinction hypothesis, the asteroid impact theory is the most popular, which believes that the asteroid (later some scholars believe that comets are more likely) is the culprit that kills the dinosaurs.

There are many reasons for the extinction of dinosaurs, but two are more convincing.

1. It may be due to a volcanic eruption, and then **.

2. It may be caused by a meteorite impact. Meteorites hit the earth and produce a large amount of gas that accumulates in the atmosphere, so that sunlight cannot reach the earth, and plants cannot carry out light and function and die. Then the plant-feeding animals (including the herbivorous dinosaurs) died, and the carnivorous dinosaurs died without food.