When sand enters the body of an oyster, after some years which process occurs?

When sand enters the body of an oyster, after some years which process occurs?

جب ریت کچھ سالوں کے بعد ایک شدت کے جسم میں داخل ہوتی ہے تو کون سا عمل ہوتا ہے؟
Explanation

When a grain of sand enters an oyster's body, the oyster secretes layers of nacre (mother of pearl) around the irritant.

Over time, these layers build up and form a pearl.