The difference between an artery and a vein is that arteries are larger, more muscular and more elastic than veins; they carry blood that is under pressure from having been pumped out of the heart; veins are under much less pressure, so they are not as strong
Answer: Vestigial structures
Explanation: Vestigial structures are an anatomical feature or behavior that no longer seem to have any purpose in the present form of an organism in the given species. Usually, they are often parts of the body that used to preform important functions in earlier forms of the organism.