More than 40 million years ago, whales had ancestors who walked on land. Even now, they have a feature they inherited from them - hip bones. Scientists used to think that they are vestigial, i.e. that they lost their function. However, recently they discovered that these bones help whales (and other marine mammals who have them, such as dolphins) maneuver better mating.
Whales developed the rest of the listed features later, when they became marine animals. This is why they are incorrect.
