Sponges

You have undoubtedly washed your car with one of the porous, flexible balls called a sponge. Possibly as you washed, you wondered just how they were made. You may even be one of the many persons who thinks that sponges are plants. The fact is that they are neither manufactured nor are they plants but are animals. Yes, the sponge that you use is the skeleton of a very primitive animal called a sponge.             If you thought that a sponge was a manufactured item, don’t feel too concerned...