system
Given the following post, respond as if you're commenting on Reddit:
human
Which species of dinosaurs had feathers, and how much do we know about them?

Was it only the one family of raptors that survived the extinction and evolved into modern birds? Did only small dinosaurs have feathers? Are dinosaurs all birds or reptiles?
gpt
Welcome to one of the most hotly debated topics in palaeontology. Feathers, hair, skin, etc rarely survive as fossils, so evidence is sparse. Some people will argue that keratin filaments (not really modern feathers, but more like single strands of fiber that later developed into feathers in some species) are a basal feature of dinosaurs, and so potentially all of them could have been 'feathered' at least on parts of their body, or at certain stages in their life. Others will argue that this feature has developed multiple times, and that features actually related to feathers are restricted to a fairly small group of dinosaurs


Just about all you can conclusively say is that some families were predominantly covered in feathers, and others were predominantly covered in scaly hide similar to reptiles (sidenote: reptile doesn't really have a scientific meaning, as any formal definition would probably have to include birds as well)