Are sponges living oganism

Yes they are,

Sponges are animals of the phylum Porifera (pronounced /pɒˈrɪfərə/). Their bodies consist of jelly-like mesohyl sandwiched between two thin layers of cells. While all animals have unspecialized cells that can transform into specialized cells, sponges are unique in having some specialized cells that can transform into other types (Source wikipedia) I also have a couple of them living with me at home but that's another story.