in the water
There are many different kinds of sponges. Every time you see a sponge with a different shape and color, that is a different species. There are thousands of different species of sponges, tube sponges, encrusting sponges, demosponges, etc. But yes, Porifera only includes sponges. So sponges are the only animals in the Porifera.
a hot dog
upright
Some examples of sponges are: Sea Sponge,Tube Sponge,Vase Sponge, Yellow Sponge , Painted Tunicate Sponge, and the Bright Red Tree Sponge. Please note that Coral and Sponges have a lot in common but are not the same.Corals are related to Jellyfish and Sea Anemones and are far more complex than sponges.
Freshwater sponges are delicate in structure, growing as encrusting or branching masses. They usually appear greenish because of the algae that live on them. Freshwater sponges may attain a volume of more than 2,500 cubic centimeters (150 cubic inches). Marine sponges are natural bath sponges (with living cells removed) that we all are familiar with. They actually are the oldest and simplest animals that have been living on earth for millions of years. Marine sponges are filter-feeding animals because all adult sponges are sessile and can't move around benthic surface. Marine sponges have no true tissues or organs, just constructed with layers of cells even without nervous system. Marine sponges come in different but striking colors, bright red, purple, yellow, and brown, etc. These colors and some are toxic as well may help them defend from sponge eating invertebrates and some fishes. Some other small marine organisms, fishes, and microscopic organisms often call marine sponges their homes. There are no terrestrial sponges because they are filter feeders obtain from water particles.
it is upright. it releases gas through a crack on its underside
No, sea sponges are not decomposers. Sponges are filter feeders.
no sponges are not unicellular.
No, sponges are not parasitic.
no sponges do not have bones
Sponges are asymmetrical, although a few species have nearly radial symmetry.