Product Research
Research the various Perms/Relaxers products used in salons. Make a chart of the products listing name, pH, key ingredients, and hair type for which they are recommended.

its probably to later but whats the question

fumikage isn't really a bird, and tsuyu does have teeth. tsuyu has a transformation quirk which still allows her to be partially human. otherwise we'd have a large frog running around. fumikage has teeth because again, he isn't a bird. his head was a quirk mixture if i'm correct.