The skeletons of a baleen whale and a hummingbird show the similarities between their hind limbs, ribs, phalanges, radii, ulnae, humerouses, and skulls.
The bone structure of the baleen whale and the hummingbird pictured above suggests that they share ____ .

Select one:
a. a similar environment
b. the same diet
c. similar mating rituals
d. a common ancestor