What is your explanation of how and why dinosaurs became extinct?

Well the main theory is the asteroid theory. I agree that it was an asteroid as there is a lot of evidence for it. For example, there is a layer of iridium covering the earth which is found in asteroids. also there is a crater in Mexico called the Chixulub crater which is said to be from 65 million years ago at the time of the dinosaur's extinction. Also the impact of an asteroid hitting earth would have caused the earths atmosphere to be filled with dust, therefore blocking off the sun so photosynthesis wouldn't happen so plants would die, herbivores would die as there would be nothing for them to eat and the same for predators so there would be no dinosaurs left.