It is pretty common for me to double-check things before I post, which makes me look smarter than I would in a real-time conversation if I stopped to look something up 
There actually are quite a lot of things I don't know. But I can't easily give a list, because I don't spend much time thinking about those things.
Regarding chickens and teeth:
https://www.npr.org/2006/02/23/5230538/study-of-chicken-teeth-sheds-light-on-evolution
"A new study shows that chickens, which don't have teeth, still have the genes that make them, and in special cases, those genes can be switched back on...."
And another article on the same subject:
https://www.scientificamerican.com/article/mutant-chicken-grows-alli/
(For that one, I knew what terms to put into a search engine to find the answer. I thought I'd read something about it before, but I didn't remember in enough detail to be able to explain it off the top of my head.)