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Animals devoid of respiratory, excretory and circulatory organs are
A. Tapeworms
B. Sponges
C. Threadworms
D. Live fluke

Last updated date: 11th Jun 2024
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Hint:-The 'Phylum Porifera' refers to species devoid of infectious, circulatory and excretory glands. They are diploblastic creatures, multicellular, typically aquatic and sedentary, often free-floating. True tissues lack them.

Complete answer:
Tapeworms have no intestine or mouth and consume nutrients through their adapted neodermal cuticle, or tegument, from the food tract of the host, through which gas exchange often takes place. The tegument also protects the parasite from the digestive enzymes of the host and helps molecules to be passed back to the host. Sponges, composed of jelly-like mesohyl sandwiched between two thin layers of cells, are multicellular species that have bodies full of pores and channels that cause water to flow through them. They have unspecialized cells that can turn into other forms, often migrating in the process between the main cell layers and the mesohyl. Nervous, metabolic or circulatory processes do not occur in sponges. Instead, to receive food and oxygen and to eliminate waste, most rely on maintaining a steady water flow through their bodies. Sponges have an opening called the Ostia from which water reaches the body and through radial tubes lined with flagellated cells. Via an opening called the Oscula, water is moved out. Respiration takes place by the water's oxygen diffusion, circulation takes place through the canal system, and ammonia excretion occurs through pores. Liver flukes are leaf-like and compressed throughout the body. The body is surrounded by a tongue. They are hermaphrodites with full sets of reproductive systems for both males and females. They have basic digestive processes and they feed on blood mainly. The oral sucker that opens into the mouth is the anterior end. Within, the mouth connects to a tiny pharynx, accompanied by a swollen intestine that passes along the body's entire duration.
From these discussions we can conclude that sponges are devoid of respiratory, excretory and circulatory organs.
Thus, the right option is B.

Note:- Sponges were the first to break out from the common ancestor of all animals from the evolutionary tree, making them the sibling group to all other animals. Even if a few sponges are capable of producing mucus, which in all other species serves as a microbial shield, no sponge has been documented with the capacity to secrete a functioning mucus layer. Without such a mucus coating, a coating of microbial symbionts protects their living tissue, which may add up to 40-50 percent of the wet sponge mass. This failure to inhibit the intrusion of microbes into their porous tissue may be a big explanation that a more sophisticated anatomy has never developed.