This is a biology paper about the Phylum Porifera!!! Uses the example of Sponges(a member of the phylum Porifera)

The Phylum - Porifera Sponges are the simplest of the multicellular animals. They are characterized by numerous canals, tunnels, and chambers that open to the outside by way of pores which giving this phylum its name. They are ancient but age isn't enough to prove that they are our ancestors. Sponges do not have a nervous system, brain or any organs. Their body is defined by a system of cells and they have no shape. …

…one ounce of food. Sponges actively pump water through its tiny canals and chambers. The interior of the sponge is lined with flagellated cells called choanocytes. This helps the movement of which creates currents that force water through the sponge's "plumbing system". A sponge's sex life depends on its pumping. Also, they were one of the first animals to reproduce sexually. Sponges are living thriving animals. They continue to strive in this diverse crowded world.