The Day the Mesozoic Died

What the video was explaining how scientists hypothesized how the Mesozoic era died. There hypothesis was that an astroid landed on earth and with the energy from that killed off all the reptiles and dinosaurs. As they look at the KT boundary they find lots of dinosaurs before it they found dinosaur fossils and remains, but after that they don't find anymore. Scientists are still trying to solve some of these mysteries, but they think they figured this one out.