NEET BIOLOGY

Detailed explanation-1: -Phylum Porifera is a group of simple animals that includes the sponges. Porifera have no internal organs, nervous tissue, circulatory system, or digestive systems, making them the most primitive of the multi-cellular animals.

Detailed explanation-2: -Sponges are primitive multicellular animals and have a cellular level of organization. Sponges have pores all over the body that provide the pathway to the water for food gathering, respiratory exchange, and removal of waste. There is no grouping and coordination of the body cells to form the tissues.

Detailed explanation-3: -The phylum of sponges (Porifera) contains sessile organisms, most of which live in marine habitats. The few species of freshwaters all belong to the class of demosponges (Demospongiae).

Detailed explanation-4: -All adult sponges are sessile aquatic animals, meaning that they attach to an underwater surface and remain fixed in place (i.e., do not travel) while in larval stage of life they are motile.