There are 5 biological kingdoms: Animalia, plantae, fungi, monera, and protista.
Plantae groups plant cells characterized by chlorophyll.
Monera groups prokaryotic organisms such as bacteria.
Fungi groups eukaryotic cells such as yeasts
Protista groups unicellular eukaryotic organisms such as amoebae.
The animal kingdom groups multicellular eukaryotic organisms that can therefore form tissues.
Sponges are primitive animal organisms, so they do not have embryonic development like other known animal organisms. However, the cells that make up the sponge are grouped and interact performing different functions of vital importance as in tissue.
Because of how they are organized and how they function, we can see that the definition of sponge fits only with the definition of the animal kingdom.
