Since all organisms share a common ancestor,it comes as no surprise that some characteristics are shared while others are not.If we consider the backbone and feathers,respectively,of birds,we can say that the former is a while the latter are a .

Question

Since all organisms share a common ancestor,it comes as no surprise that some characteristics are shared while others are not.If we consider the backbone and feathers,respectively,of birds,we can say that the former is a ________ while the latter are a ________.