Sea sponges are considered to be some of the simplest of multi-cellular animals on earth. They have neither a central nervous system nor a brain yet the various types of cells within a sea sponge are able to perform the many different functions necessary for life. One amazing characteristic of sea sponges is their ability to regenerate. They are able to rebuild parts of their body structure that have been broken off, but it goes far beyond this. There is an interesting experiment that has been performed in laboratories around the world that demonstrates the remarkable regenerative ability of this simple creature.