Why is uranus sometimes called the sideways planet

Uranus is called the sideways planet because it rotates a different way than any of the other planets in the solar system. Uranus rotates on its side, perpendicular to the north-south orientation of Earth and other planets. For this reason, Uranus is sometimes called the sideways planet.

the endomembrane system i think

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.