I have had young children, but have also been one. Besides the pterosaurs, I recently learned that proper dinosaurs appear to have evolved flight in at least f

I have had young children, but have also been one. Besides the pterosaurs, I recently learned that proper dinosaurs appear to have evolved flight in at least four separate lineages, independently. The feathers came first. Doubt anybody will ever know why only Aves survived. I have seen a claim that the only birds that survived were flightless, and had to evolve flight all over again. (I might have misunderstood something.) Sauropods are to me the most mystifying of the proper dinosaurs, for purely mechanical reasons. So many unanswered questions. svpow.com