Vertebrates are group into the phylum of chordate. <span>Although all the chordate physically have a great differences but during the embryonic development there are 4 similar structure: </span> <span>1. have gills(which depend on which class if for fishes the gills will use for respiration if for mammals gills will develop for hearing) </span> <span>2. have notochord( which will develop into back bone） </span> <span>3。nerve chord </span> <span>4. tail </span>
