Answer: Porifera shows cellular level, Cnidaria shows tissue level, Platyhelminthes shows organ level.
- A Porifera shows organ-system level with coordinated organ function, Cnidaria shows mainly cellular level
- B Porifera shows cellular level, Cnidaria shows tissue level, Platyhelminthes shows organ level
- C All three phyla independently evolved a largely coordinated organ-system level of organization
- D Cnidaria shows organ-system level of organization that exceeds that of Platyhelminthes
Correct answer: B. Porifera shows cellular level, Cnidaria shows tissue level, Platyhelminthes shows organ level
Explanation: Levels of organization increase in complexity: Porifera has cellular level organization, Cnidaria has tissue level, and Platyhelminthes (and other higher phyla) have organ level, progressing to organ-system level in Annelida onward.
Moving across the animal phyla, body organisation becomes progressively more complex: from no symmetry and cellular organisation (Porifera) through radial/diploblastic (Cnidaria), bilateral/acoelomate (Platyhelminthes), pseudocoelomate (Nematoda), to a true coelom with full organ systems (Annelida and beyond).
Concept context
Phylum-level classification of the animal kingdom from Porifera to Chordata, based on body symmetry, coelom, and segmentation. One of the most example-heavy chapters for NEET.