Homologous structures is when very different animals have bones that appear very similar in form or function and seem to be related. For example, a dolphin's flipper, a bird's wing, a cat's leg, anf the human arm.
Analogous structures are structures of different species that have similar or corresponding functions, but are not from the same evolutionary origin. Fore example, wings of insects and wings of birds. Theyre both used for flying, but the species are not related.
Vestigial structures are structures that at some point had a purpose, but no longer serve them. For example, the human apendix.
