(1) like diamonds, pearls are highly valued and prized for both their beauty and their rarity. (2) a pearl is mostly made of calcium carbonate, which also forms marine organisms like coral and sea urchins.(3) pearls are produced by mollusks, such as mussels, oysters, clams, and snails. (4) mollusks are invertebrates with a soft body, usually protected by a shell. (5) when any tiny object gets inside (such as a small piece of shell), mollusks protect their delicate bodies by coating the object with calcium carbonate.(6) this then becomes the tiny "seed" of a pearl. (7) large pearls take a few years to grow, and it is very hard to find ones that have a perfect round shape. (8) over time, the pearl gets bigger as the mollusk keeps coating the foreign object with layers. (9) generally speaking, bigger pearls are considered rarer and more valuable. (10) these large pearls are quite rare and very expensive.

which sentence in this passage is in the wrong place?

select one:
a.
sentence 10
b.
sentence 7
c. sentence 2
d. sentence 5