EVERYDAY SCIENCE

Detailed explanation-1: -All freshwater sponges belong to the class Demospongiae, the most diverse and morphologically complex of the four major groups in the sponge phylum. Within the demosponges, the evolutionary history of the freshwater sponges is long and polyphyletic.

Detailed explanation-2: -The phylum Porifera comprises the sponges. Sponges are simple invertebrate animals that live in aquatic habitats.

Detailed explanation-3: -Sycon and Euspongia are marine sponges, while Spongilla is a freshwater sponge.

Detailed explanation-4: -Demosponges are the sponges most commonly seen whilst diving or walking along the shore. Unlike the other two classes whose members are all marine, demosponges can also be found in freshwater. In the past, these sponges were used as bath sponges.