What changes do you see in the limb structure of three animals above?

To accurately answer your question about the changes in limb structure of three specific animals, I would need more context regarding which animals you are referring to. However, in general, limb structures can vary significantly among animals due to adaptations to their environments and lifestyles. For instance, birds have evolved lightweight, elongated wings for flight, while aquatic animals like whales have modified their forelimbs into flippers for swimming, and terrestrial mammals like horses have developed strong, elongated limbs for running. These adaptations illustrate how different environments shape the morphology of limbs across species.