I want to know the answer to the following question:
Analysis of what genome has emphasised the importance of sponges, placozoans, and choanoflagellates  in explaining the arrival of 1500 ancestral genes unique to the Eumetazoa?
All the background I'm provided with is that "This was facilitated by the severely reduced state of their genomes, but as many genes, introns, and linkages lost, these ecdysozoans can teach us little about the origins of animals in general.". Is that enough to answer the question?