The structures are evidence of evolution in that all living things are homologous with a genetic code which is extremely similar though other genetic code exists and then it suggests a common ancestor.
Human harm is considered homologous structures together with bird’s wings, cat’s legs. A human being has bones for example ulna, fingers, and wrist bones that features appear similar to ones in other animals. Bat’s whales have similar homologous structures which demonstrate that these creatures have a common ancestor.