What does phylogenetic evidence tell us about protostomes?

There were multiple transitions from water to land.

Explanation:

Protostomes are species whose mouth develops near the blastopore such as mollusks, annelids, and arthropods. Protostomes originated alongside deuterostomes and xenacoelomorphs. Deuterostomes anus forms near the blastopore and mouth form at the other end.  These distinct adaptation patterns were observed in living taxas and are believed to evolve in the gaps of phylogenetic pattern during the transition from water to land.  

In metazoans phylogeny, such gaps are frequent in protostomes and deuterostomes. The differences in the embryonic development depicts changes induces through transition.

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did you fail the test? xd