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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Definitions:

Acid-Base Reaction

A chemical reaction that involves the transfer of a proton (H+) from an acid to a base, resulting in the formation of a conjugate base and a conjugate acid.

Equilibrium

The state in which the concentrations of reactants and products in a reversible chemical reaction are unchanged over time, indicating a balance in the rate of forward and reverse reactions.

Synthetic Route

The planned sequence of chemical reactions used to convert starting materials into desired products in the laboratory or industry.

Reagents

Chemical substances that are employed to bring about a chemical reaction in a provided set of reactants.