What's inside a clam? A retractable foot, a siphon for sucking up water, powerful muscles, and, sometimes, a pearl. And you thought ... mollusk that's encased in a shell made of two valves ...

Pearls are made by marine oysters and freshwater mussels as a natural defence against an irritant such as a parasite entering their shell or damage to their fragile body. The oyster or mussel slowly ...

Remember, "skeletons" include bone, the protein shell ... clam shells. All are made largely of aragonite, the original shell material. The recent shells retain the organic material that give the ...

Pearls are the ... growth is spread over the shell's surface in the unmistakable shape of a fish. Pearlfish are small, ocean-dwelling fish, often found in tropical waters. These translucent animals ...