Water can exist in three states of matter. imagine examining the changes of state from solid to liquid to gas by to ice.

by adding heat to ice.

Explanation: The three states of matter are solid, liquid and gas. Ice is water in solid state. When ice is heated, it melts and changes from solid state to liquid state. When more heat is applied to water in its liquid state, it boils and changes to vapour which is gas. Water vapour exists in gaseous state.

answer; ///i believe that the correct answer is (a) specialized cells)

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.