The structure that is common in the embryos of mammals, amphibians, birds, fishes and reptiles and which is an evidence of their common ancestry is the

The structure that is common in the embryos of mammals, amphibians, birds, fishes and reptiles and which is an evidence of their common ancestry is the

Answer Details

The structure that is common in the embryos of mammals, amphibians, birds, fishes, and reptiles and which is an evidence of their common ancestry is the gill-slits. Gill-slits are openings found in the pharynx region of the embryos of these animals. Although these structures have different functions in different groups of animals, their presence in the embryos of different vertebrates is a clear indication of their shared evolutionary history. The gill-slits develop into different structures in different animals, for example, in fishes they develop into gills, in reptiles, birds and mammals, they develop into different structures like the middle ear cavity, parathyroid gland, and thymus gland.