Explain why the water in the river and on the banks is the same substance​

it's c. (to reduce the greenhouse effect/carbon gasses)

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.

c is the correct answer!