Question

Which one of the following is a freshwater sponge?
A. Spongilla
B. Sycon
C. Euspongia
D. Euplectella

Answer 1

Hint: Sponges belongs to the phylum Porifera, they are pore=bearing animals. Sponges are aquatic in habitat either in the freshwater or marine water. The water canal system or canal system is present in the sponges.

Complete answer:
In sponges, a water canal system or canal system is present. Minute pores i.e. ostia are present in the body wall through which water enters and goes into the central cavity known as spongocoel. Through the osculum, water goes out. This transportation helps in gathering food, waste removal, and exchange of respiration.
A. Spongilla- Spongilla is a genus of freshwater belonging to the family Spongillidae which is mainly found in the lakes or slow streams. Sponges of the genus Spongilla attach themselves with the rock or logs and filter the water for small aquatic organisms like bacteria, protozoans, etc.
B. Sycon- Sycon is a genus of calcareous sponges belonging to the family Cottidae. Sycon is mostly found in shallow water. These sponges are small and are tube-shaped.
C. Euspongia- Euspongia belongs to the family Demospongiae and is mainly found in the marine. Euspongia has a skeleton made of spongin fibers. It has economic importance.
D. Euplectella- Euplectella genus comprises marine sponges. These sponges are also known as glass sponges because siliceous spicules are present. Euplectella includes Venus flower baskets. They are found in marine water or deep in the ocean.

Hence, the correct answer is option (A).

Note: Phylum Porifera has advanced over the phylum protozoa and has a multicellular body. The presence of Ostia, canal system, or spicules makes this phylum unique, and they are widely found in freshwater.