Concept:Sponges are simple, porous, aquatic animals that exclusively belong to the phylum Porifera.
Explanation:Porifera literally means "pore-bearing," which describes the sponge's body structure.
Their bodies have numerous holes called ostia for water entry and oscula for water exit.
This constant water flow helps them in filter feeding, respiration, and waste removal.
They possess specialized flagellated cells known as choanocytes (or collar cells).
These choanocytes line the internal cavity (spongocoel) and canals to generate water currents.
Sponges have a cellular level of organization and lack true tissues or organs.
Their skeleton is made up of tiny spicules or flexible spongin fibers.
Digestion in sponges is entirely intracellular.
They can reproduce asexually through budding or fragmentation.
Sexual reproduction also occurs, and most sponges are hermaphrodites.
Fertilization is internal, leading to a free-swimming larval stage.
Examples of Porifera include Sycon, Spongilla (freshwater sponge), and Euspongia (bath sponge).
The other phyla listed do not correspond to sponges:
Coelenterata (Cnidaria) includes organisms with stinging cells, like jellyfish.
Platyhelminthes includes bilaterally symmetrical flatworms, such as tapeworms.
Echinodermata includes spiny-skinned animals with radial symmetry, like starfish.
Therefore, based on the defining characteristics, Porifera is the correct phylum for sponges.
Answer:Option C (Porifera).