the precious commercial pearl is produced by ___
a)unio
b)pinctada
c) octopus
d) Pila
Answers
The precious commercial pearl is produced by Pinctada.
So, the correct choice is option (B)
Explanation:
•Pearl is actually a globular concretion which is white in colour and is highly shiny. These are formed inside the shell of osyters and also in other bivalves.
•The organism Pinctada actually belongs to family of Pteriidae. These are commonly also referred as the pear oysters. They has the ability to produce pearls in large numbers.
•It is mostly accepted that formation of pearls occurs because of the irritation which is caused when some foreign substances enters the mantle cavity.
•Chemically, pearls has calcium carbonate (about 90%), organic substances (about 5%), water (5%) and other residues and substances.
•More the degree of irritation occurs by the foreing agents, bigger the size of the pearl is produced.
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