Question

multiple choice question
animals in phylum ______ have radial symmetry, a gastrovascular cavity, and a body composed of a layer of ectoderm and a layer of endoderm.
○ platyhelminthes
○ cnidaria
○ porifera
○ mollusca

Explanation:

• Phylum Platyhelminthes: Have bilateral symmetry, not radial.
• Phylum Cnidaria: Radial symmetry, gastrovascular cavity, diploblastic (ectoderm and endoderm layers).
• Phylum Porifera: Asymmetrical or slightly radially symmetrical in some, no gastrovascular cavity in the true sense.
• Phylum Mollusca: Bilateral symmetry.

Answer:

Cnidaria.