A whale's flipper may look like a fin built purely for swimming. But underneath, a whale has the same five-digit bone structure as a bat or a human, including a wrist connected to the same cluster of carpal bones connected to the same long forearm bones. What can be more curious than that the flipper of a whale, built for swimming, the wing of a bat, built for flight, and the hand of a human, built for grasping, should all be constructed on the same underlying pattern?

Which one of the following is the most logical, scientific and rational inference that can be made from the above passage?