Page 9 - Reading Success B1

Pearls form inside the shells of certain oysters and other kinds of mollusks. The
pearl begins to form when a tiny particle, such as a grain of sand or a living

parasite, gets inside the shell. The oyster coats the particle with a layer of smooth
material called nacre. The nacre protects the body of the oyster from being

irritated by the parasite or grain of sand. As time goes by, more layers of nacre
are added, and gradually a pearl is formed.

Many mollusks besides oysters form pearls. Conches produce pink pearls.
Pearls from some mollusks are a silvery black color. Cultured pearls are produced

when a person places a tiny bead inside the oyster shell. The oyster covers the
bead with nacre, and a large, round pearl is produced. Cultured pearls have

been produced since the early 1900s, especially in Japan, where culturing pearls
has become a major industry.

There are still some pearl divers, people who dive underwater to gather oyster
pearls. Natural pearls are pearls produced without any help from people. River

pearls are produced by freshwater mussels.

Main Idea

What is the main idea of this story?

a. certain types of shells and oysters

b. nacre that protects the body of an oyster
c. divers in search for precious pearls

d. how pearls are formed and produced

12_Reading Success B 1