"Sponges are similar to other animals in that they are multicellular, heterotrophic, lack cell walls and produce sperm cells. Unlike other animals, they lack true tissues and organs, and have no body symmetry. ... All sponges are sessile aquatic animals." http://www.patreon.com/raocow https://talkhaus.raocow.com/viewtopic.php?f=3&t=17447