Sponges have true tissues, but do they have many?

They don't have true tissues.Sponges do not have internal organs.They have no muscles, a nervous system or a circulatory system.Their walls are lined with small pores that allow water to flow into the sponge.

Do sponges have skin?They can develop true tissue with the help of the endoderm.Sea sponges lack true tissue organization and have one germ layer.All the more complex animals are triploblastic with three germ layers.

nidarians are said to be the simplest organisms at the tissue grade of organization, as their cells are organized into true tissues.The bags are made of two cell layers.The cnidocysts are stinging cells that are characteristic of the phylum.

Sponges are the only multicellular animals that don't have a nervous system.They don't have any sensory cells.Touch or pressure to the outside of a sponge will cause a contraction of the body.