حبليات: الفرق بين النسختين

}}

<ref>{{مرجع كتاب

| الصفحة=7

}}"<cite>Classifications of organisms in hierarchical systems were in use by the seventeenth and eighteenth centuries. Usually organisms were grouped according to their morphological similarities as perceived by those early workers, and those groups were then grouped according to ''' their''' similarities, and so on, to form a hierarchy</cite>"

</ref> and is defined by having at some stage in their lives all of the following:<ref name="RychelSmithShimamotoSwalla2006">{{cite journal

| volume=23

| pmid=16280542