The research party began by exploring the embryonic development of whales' cousins, the dolphins. These creatures are intriguing because, for a brief time during development, they sprout hind limbs . That's why dolphins lose their 'legs'.” In whales, however, the story is more complex.
Answer:
I think that the answer is c. If not then it is probably d or a.
I believe this is the answer you are looking for:
<span>C. The size and shape of their beaks</span>
