what are two characteristics that are unique to sponges
1 Sponges are filter feeders, who absorb nutrients as well as oxygen from the water, that enters its body through the pores. 2  Usually, they feed on bacteria and food particles present in the water; but, some species have a symbiotic relation with certain microorganisms. So, sponges are made of these specialized cells, and they do not have any head, trunk, bodily organs, or appendages. 2  They are simple multicellular organisms. 3  Sponges are filter feeders, who absorb nutrients as well as oxygen from the water, that enters its body through the pores.