Although Animals as Complicated as the Sponges Exist in the Fossil

question 76

Multiple Choice

Although animals as complicated as the sponges exist in the fossil record before 530 MYA,the common phyla we can observe in living animals now appear in the fossil record only abruptly in a short span of 25 million years.When researchers analyzed the DNA evidence that might relate sponges to the modern phyla,what unexpected result did they find?

• A) The entire genome of sponges was found to be very different in gene diversity from the genomes of other phyla.
• B) Samples of the living sponge, Oscarella carmela, were found to be relatively unchanged from fossil sponge DNA samples.
• C) DNA evidence indicated clearly that a sponge like Oscarella carmela was the common ancestor of eumetazoans.
• D) All of these answer options are correct in expressing unexpected results from the research.
• E) Many development genes thought to be specific to eumetazoans were found in sponges.

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