'(Sarah of the Clue Crew scuba diving in the Barrier Reef near Belize)  Sponges are classified based on what this structure is made of, such as calcium carbonate or silica'
the skeleton
THE NATURAL WORLD: Sponges are classified based on what this structure is made of, such as calcium carbonate or silica
Sponges are classified based on what this structure is made of, such as calcium carbonate or silica
Sponges are classified based on what this structure is made of, such as calcium carbonate or silica
THE NATURAL WORLD
the skeleton
THE NATURAL WORLD