Answer:
homologous structures (wings, fins, etc)
Step-by-step explanation:
homologous structures are different than the opposite which are human hands for example. if you look at the anatomy of a human hand compared to a wing, you will see that humans hand have more bone structure than wings.
fun fact: by looking at animals X-rays of their hands wings etc, you can tell sort of where they evolved from. for example by looking a monkey's hands, we can tell that they evolved from either monkeys or humans and vice versa.