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Multiple Choice
The Deuterostomia clade includes which two phyla?
A
Cnidaria and Platyhelminthes
B
Arthropoda and Mollusca
C
Echinodermata and Chordata
D
Annelida and Nematoda
Verified step by step guidance
1
Understand the term 'Deuterostomia': Deuterostomia is a clade of animals characterized by their embryonic development, where the first opening (the blastopore) becomes the anus, and the mouth forms secondarily. This is distinct from Protostomia, where the blastopore becomes the mouth.
Review the major phyla within Deuterostomia: The two primary phyla in this clade are Echinodermata (e.g., starfish, sea urchins) and Chordata (e.g., vertebrates, tunicates). These groups share developmental and genetic traits that classify them as deuterostomes.
Eliminate incorrect options: Cnidaria and Platyhelminthes are not deuterostomes; Cnidaria are radially symmetrical animals, and Platyhelminthes are protostomes. Similarly, Arthropoda and Mollusca are protostomes, and Annelida and Nematoda are also protostomes.
Confirm the correct answer: Echinodermata and Chordata are the only phyla listed that belong to the Deuterostomia clade, based on their shared developmental characteristics.
Summarize the reasoning: The correct answer is Echinodermata and Chordata because they are the two phyla that exhibit deuterostome development, distinguishing them from the other options provided.