Why are dinosaurs becoming extinct animals?

Why did dinosaurs become extinct for over 100 million years? Dinosaurs were the dominant form of life on earth, and they were the largest animal on the planet. The last dinosaurs died about 65 to 70 million years ago. The reason for their extinction is still a scientific mystery. There are various theories about why this extinction happened, but none have been proven yet.
 
Earthquake significant asteroid impacts on earth could send seismic waves causing super volcanic eruptions that helped wipe out the dinosaurs and other creatures volcanoes; some of the research suggests heavy lava flow from the Deccan Traps in western India may have spewed poisonous levels of carbon dioxide and sulfur into the atmosphere and cost the extinction.

Disease several paleontologists say dinosaurs did suffer from diseases like parasites, hay fever, specific allergic reactions, and bone infections; mammals dinosaurs and mammals evolved during a similar period. Maybe mammals destroyed or ate the eggs of dinosaurs, driving them to extinction.

Several paleontologists suggest the ice age could have frozen water, and dinosaurs could not survive. They slowly died out, but scientists have no evidence of an ice age occurring during the life of the dinosaurs.
Food chain imbalances led to the starvation of the dinosaurs and may cost their extinction. Most paleontologists believe that birds and crocodiles are the only surviving dinosaurs, so they aren't extinct because their descendants are still living, but there is no solid evidence of this. We should try to save wildlife habitat to save the animals wildlife should have places to find food shelter and raise their young by protecting the entire habitat communities of animals and plants can be protected. 

Asteroids, a recent explanation suggests that dinosaurs went extinct after a giant meteorite crashed to earth near the Gulf of Mexico. The giant meteorite could have landed with lots of debris and dust and blocked sunlight for an extended period; due to this, many deadly events started without the sun rays; all the plants died without the plants, all the plant-eaters died, and without the plant-eaters, all the carnivores died.