Multiple choice Which of the following phyla possess all the three germinal layers? Porifera Coelentrata Platyhelminthes Cnidaria None of these Reveal answer Fill a bubble to check yourself C Correct answer Explanation Those animals in which the developing embryo has a third germinal layer, mesoderm, in between the ectoderm and endoderm, are called triploblastic animals e.g. platyhelminthes to chordates.