What do scientists believe caused the extinction of dinosaurs. One answer only?

Scientists primarily believe that the extinction of dinosaurs was caused by a catastrophic asteroid impact, specifically the Chicxulub impact event around 66 million years ago. This event likely led to drastic environmental changes, including wildfires, tsunamis, and a "nuclear winter" effect that drastically altered the climate. Additionally, volcanic activity from the Deccan Traps may have contributed to the extinction by releasing massive amounts of gas, further destabilizing the environment. Together, these factors created conditions that many species, including the dinosaurs, could not survive.