Question

Read the following statements and choose the correct option.
Assertion (A): Nacre is secreted continuously by the epithelial layer of the mantle
deposited around the foreign particle and over a period of time the
formation of repeated layer of calcium carbonate makes the hard and
glossy pearl.
Reason (R): The pearl comprises of 2 - 4% water and 90% calcium carbonate.
Statement (A) is incorrect but statement (R) is correct.
(b) Both statements (A) and (R) are correct and (R) is the correct explanation to (A).
(c) Both statements (A) and (R) are correct but (R) is not the correct explanation
to (A).
(d) Statement (A) is correct but statement (R) is incorrect.
І
т.
rar

Answer 1

Answer:

I don't understand your qwetion. . . . . . . . .....aryan bri

Answer 2

(c) both statements (A) and (R) are correct but (R) is not the correct explanation

• Nacre is secreted by the epithelial cells of the mantle tissue of various mollusks
• The nacre is synthesized and deposited onto the inner surface of the shell in the form of the iridescent nacreous layer that is generally referred to as mother of pearl.
• The layers of nacre help defend the soft tissues against parasites and damaging debris by enclosing them in successive layers of nacre, forming either a blister pearl attached to the interior of the shell, or a free pearl within the mantle tissues.
• The process is called encystation and it continues as long as the molluscan lives.