What Is a Sponge?
A sponge is an extremely simple kind of water animal with a soft, elastic skeleton. It has no head, mouth, or brain. Sponges hatch from eggs. The baby sponge attaches...
Read MoreA sponge is an extremely simple kind of water animal with a soft, elastic skeleton. It has no head, mouth, or brain. Sponges hatch from eggs. The baby sponge attaches...
Read MoreWhat Types of Technology Do Invisible Fences Use? Some invisible fence systems feature wires buried in the ground around a set perimeter, such as a yard. A transmitter...
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