Questions & Answers

Canal system of Porifera is not connected with
A. Nutrition
B. Sexual Reproduction
C. Respiration
D. None of the above

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Hint: Members of the phylum Porifera are commonly known as sponges. This is a phylum that comes under the Kingdom Animalia. They are multicellular organisms. They are believed to be the first to be branched off the evolutionary tree from the common ancestor of all other animals thereby these are considered as the sister group of all other animal groups and most evolutionary animals.

Complete answer: Sponges have multiple spores or canals in their body. They have a water transport system or also known as a canal system. These minute pores in their body are called Ostia. Water enters through these Ostia into the central cavity called spongocoel and exits through the osculum.
As such sponges do not have a circulatory, nervous, and digestive system, they have a general body appearance and are primitive.
Option -A- Nutrition
Nutrition or food gathering in sponges is through the canal system. They take tiny floating organic particles, bacteria, and also plankton via water through the canal system. The food particles are ingested by specialized cell choanocytes present in the canal system.
Option -B- Sexual reproduction
In sponges, they have both sexual and asexual modes of reproduction. Sexual reproduction is with the involvement of male and female gametes. Fertilization is internal and indirect development that occurs with the larval stage. Sex cells are formed from the chondrocytes of the canal system.
Option -C- Respiration
Water continuously flows in and out of the body of the sponge because of the canal system therefore the gases diffuse between the cells of the canal system and the flowing water. They lack any special structure of respiration such as lungs, gills, etc. Therefore gaseous exchange takes place via the canal system.
Option -D- None of the above
This option is not the correct description of this question because all the above-mentioned options are correct. So this option is neglected as such and is the incorrect option.

So, the correct option to this question is the option"D".

Note: Sponges have a cellular level of organization. Like other animals, they do not have cell walls, are heterotrophic and they produce sperm. They mostly have asymmetrical body appearances taking different shapes. They are mostly marine.