Each cell is in direct contact with the water so its excretory and respiratory functions are taken care of individually by each cell. They exhibit radial symmetry and in some cases no symmetry at all. Many of them form large colonial groups that serve as havens for fish and other aquatic life. They reproduce through the process of budding where an adult will grow an offspring from it side. These buds can remain attached to the parent or break off and take up residence elsewhere.
Sponges are also know to regenerate lost body parts.
Sexual reproduction is limited. Structures called gemmules are formed from amebocytes and spicules during environmental stress. Many sponges contain a large opening at the top of its body called the osculum . Water is taken into the sponge through its many incurrent pores and circulated out through the osculum. Sponges contain the protein spongin which acts as a base for the cells to cling to while forming the animal.