Question

during early stages of development, dolphin embryos begin to develop hind limbs. by the time the dolphin features are fully developed, the hind limbs have disappeared. which statement best explains the early development and then disappearance of hind limbs in dolphins? dolphin fetuses change their development to adapt to an environment. the genes that control the development of hind limbs are destroyed as the fetus develops. the early ancestors of dolphins had hind limbs. dolphins are evolving to become terrestrial animals. clear all

Explanation:

Dolphin embryos develop hind - limbs early on because their early ancestors had hind - limbs. This is an example of evolutionary vestigiality in development. The genes for hind - limb development are still present in the embryo but are later deactivated or their effects are suppressed as the embryo develops further, rather than the genes being destroyed. Also, there is no evidence to suggest dolphins are evolving to be terrestrial again, and the development and disappearance of hind - limbs is not related to environmental adaptation in this context.

Answer:

The early ancestors of dolphins had hind limbs.