The Protostome Developmental Sequence Arose Just Once in Evolutionary History

question 21

Multiple Choice

The protostome developmental sequence arose just once in evolutionary history, resulting in two main subgroups-Lophotrochozoa and Ecdysozoa. What does this finding suggest?

• A) These two subgroups have a common ancestor that was a deuterostome.
• B) The protostomes are a polyphyletic group.
• C) Division of these two groups occurred after the protostome developmental sequence appeared.
• D) The lophotrochozoans are monophyletic.

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