Question

True pearl is made up of
A. Single piece
B. Two layers
C. Many Layers
D. None of the above

Answer 1

Hint: Pearl is a well known Jewelry used in many Parts of the world, especially women. They are available in many shapes and colours. Pearl is made up of secretions made by the organisms belonging to the Phylum Mollusca. Members of this phylum who produce the pearls are known as Pearl oysters.

Complete Answer:
Mollusks are classified into various classes. The class that produces pearls is referred to as Bivalvia as they are covered by a shell that has two valves. When a parasite enters the shell or any external threat is experienced by the molluscan, it creates a pearl sac as a defense mechanism and reduces the irritation.
Pearls are formed by the deposition of calcium carbonate and a special type of protein called as conchiolin. The molluscan secretes these chemicals repeatedly in reaction to the irritant and hence pearl is formed.

Hence, the correct answer is C.) Many layers. A true pearl is made up of many layers.
The more layers of chemicals deposited, the more luster the pearl gets. The pearl producing mollusc may be freshwater or marine. Economically sold pearls are mostly cultured.
   

Note:
Pearls have been harvested and were in use since ancient times. Though they are widely used in jewelry and as decoration to clothing, they are also used in various other industries. They are crushed and the powder is used in cosmetics, medicines, paints etc. Calcium carbonate is deposited in concentric layers to form a pearl.