REMOVING floor-to-ceiling walls at the top of a stairway can turn an upstairs hallway or room into a light and airy landing and also bring increased light and openness to the stairwell. For safety, the floor surrounding the stairway must be partly enclosed. One solution is to install a railing around the opening.
A sponge is a member of the phylum Porifera. It is a simple animal with many cells, but no mouth, muscles, heart or brain. It is sessile: it cannot move from place to place the way most other animals can. A sponge is an animal that grows in one spot like most plants do.Nevertheless, sponges are quite successful. sponge is a member of the phylum Porifera. It is a simple animal with many cells, but no mouth, muscles, heart or brain. It is sessile: it cannot move from place to place the way most other animals can. A sponge is an animal that grows in one spot like most plants do. Nevertheless, sponges are quite successful.
This phylum consists of the sponges. The number of species is estimated to be between 5,000 and 10,000. All are aquatic and almost all are marine. Animals in this phyla have no true tissues, which means, for example, that they have no nervous system or sense organs.Although sponges are multicellular, they are described as being essentially at a cellular level of organization. They are sessile as adults, but have a free swimming larva. Their bodies are porous.hey are dorsoventrally compressed (i.e., flat). Animals in this phylum are acoelomate, triploblastic, bilaterally symmetrical, and unsegmented. Platyhelminths have a simple anterior brain and a simple ladder-like nervous system.