Collect the information about pearl production from bivalues by reading appropriate books.

Explanation

i. Bivalues are aquatic molluscs that have compressed bodies enclosed by a shell.
ii. Pearl oysters are examples of bivalues that can form pearl in response to an irritant or foreign particle.
iii. When any foreign particle enters in between one of the two shells of the oysters , it covers up the particle.
iv. In order to protect itself, the oyster secretes a substance known as nacre. This narce is secreted over and over in layers to cover the foreign particle.
v. Eventually , these layers create a large, shiny pearl.