Which term denotes the phylum consisting of animals with pore-bearing bodies and no true tissues?

Which term denotes the phylum consisting of animals with pore-bearing bodies and no true tissues?

• A. Radial Symmetry
• B. Swim Bladder
• C. Porifera
• D. Sirenia

Answer: (C)

Porifera describes sponges, simple multicellular animals that lack true tissues or organs. Their bodies are porous, with many small openings (ostia) and a large exit (osculum) that allow water to flow through a canal system. This pore-bearing structure is a defining feature, and they rely on specialized choanocytes to filter feed and perform intracellular digestion rather than a true digestive tract. Their body plan is supported by a skeleton of spicules or spongin, and they show cellular-level organization rather than tissue-level organization. Because of these traits, Porifera is the phylum that fits the description of pore-bearing bodies with no true tissues. The other options don’t denote this phylum: radial symmetry refers to a body plan seen in organisms with true tissues like cnidarians, not to a phylum; a swim bladder is a gas-filled organ in many fish and not a taxonomic group; and Sirenia are aquatic mammals, not a phylum.

Porifera describes sponges, simple multicellular animals that lack true tissues or organs. Their bodies are porous, with many small openings (ostia) and a large exit (osculum) that allow water to flow through a canal system. This pore-bearing structure is a defining feature, and they rely on specialized choanocytes to filter feed and perform intracellular digestion rather than a true digestive tract. Their body plan is supported by a skeleton of spicules or spongin, and they show cellular-level organization rather than tissue-level organization. Because of these traits, Porifera is the phylum that fits the description of pore-bearing bodies with no true tissues.

The other options don’t denote this phylum: radial symmetry refers to a body plan seen in organisms with true tissues like cnidarians, not to a phylum; a swim bladder is a gas-filled organ in many fish and not a taxonomic group; and Sirenia are aquatic mammals, not a phylum.