13. How are animals classified
according to the germ layers
present in their embryonic
development?

Gap-fill exercise

Fill in all the gaps, then press "Check" to check your answers. Use the "Hint" button to get a free letter if an answer is giving you trouble. You can also click on the "[?]" button to get a clue. Note that you will lose points if you ask for hints or clues!
Cnidarians are diploblastic, i.e.,
present only endoderm and .
With the exception of , all
remaining animals are .
Poriferans do not present
tissue organization and so do not
classify regarding layers (although
sometimes they mentioned as
diploblastic).