What is an explanation of why bird wings and reptile forelegs are evidence evolution?

The presence of homologous structures in different organisms is one of the main evidences of evolution. Homologous structures are those with the same basic form, despite serving different functions. For example, the forelegs of reptiles and the wings of birds are homologous structures. Although they have different functions, they have a similar basic structure, consisting of a humerus, a radius, an ulna, and a series of smaller bones. This similarity in structure suggests that these two organisms share a common ancestor that had a similar foreleg structure. Over time, the forelegs of the reptile ancestor evolved to serve a different function in birds, resulting in the development of wings. This is an example of how homologous structures can provide evidence for the evolutionary relationships between different organisms.