Question

Are mollusks protostomes or deuterostomes?

Answer 1

Molluscans are protostomes. Their mouth arise from the embryonic blastopore.

Blastopore is the opening of primitive gut that appears during gastrulation. The blastopore becomes mouth in protostomes (i.e. mouth appeared first) while in deuterostomes it forms anus (i.e. mouth appears later).

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