Very simple and quick explanation as far as I remember it - the large dinosaurs that survived the initial impact were wiped out by the ensuing 'winter' and lack

Very simple and quick explanation as far as I remember it - the large dinosaurs that survived the initial impact were wiped out by the ensuing 'winter' and lack of food (they needed a lot to sustain themselves). Plenty of smaller creatures survived including types of dinosaurs that evolved into birds. Happy to be corrected :)