Final answer:
The existence of hips in whales suggests they descended from land-dwelling ancestors, which is confirmed by vestigial structures and fossils like Rodhocetus showing a land-animal characteristic.
Step-by-step explanation:
The presence of hip structures in whales, which are aquatic mammals, suggests that these animals have a land-dwelling ancestor. This is supported by the fossil record and the concept of evolution. Structures such as the pelvic bones in whales are considered vestigial, as they are residual from when their ancestors had limbs and walked on land. The discovery of aquatic mammals like Rodhocetus having ankle bones unique to land animals further underscores this evolutionary link. Therefore, we would predict to find in the fossil record an ancestor of whales that walked on land.