Which phylum includes sponges?

Which phylum includes sponges?

• A. Chordata
• B. Arthropoda
• C. Echinodermata
• D. Porifera

Answer: (D)

Sponges are the simplest animals and belong to the phylum Porifera. They lack true tissues and organs and have bodies perforated by pores, with a cellular organization centered on choanocytes that drive water flow and filter feeding. Sponges are sessile filter feeders, drawing water in through ostia, filtering food, and expelling it through the osculum. Their skeletons can be made of spicules or spongin, and they do not have nerves, muscles, or true tissue layers like other animal groups. By contrast, chordates have features such as a dorsal nerve cord and notochord; arthropods have segmented bodies with jointed appendages and an exoskeleton; echinoderms show radial symmetry and a distinct water vascular system. Thus, sponges are classified in Porifera.

Sponges are the simplest animals and belong to the phylum Porifera. They lack true tissues and organs and have bodies perforated by pores, with a cellular organization centered on choanocytes that drive water flow and filter feeding. Sponges are sessile filter feeders, drawing water in through ostia, filtering food, and expelling it through the osculum. Their skeletons can be made of spicules or spongin, and they do not have nerves, muscles, or true tissue layers like other animal groups. By contrast, chordates have features such as a dorsal nerve cord and notochord; arthropods have segmented bodies with jointed appendages and an exoskeleton; echinoderms show radial symmetry and a distinct water vascular system. Thus, sponges are classified in Porifera.