Answer the following question given this paragraph: 

Two natural products of mollusks used for decorations and jewelry are pearls and nacre. A pearl is the hard, round object produced within the mantle of a living shelled mollusk. Pearls are produced by many bivalves when a tiny particle of sand or grit is trapped between the mantle and the shell. It's as if the mollusk has a splinter. The mollusk forms a protective covering around the irritant. Most pearls used as jewelry are made by pearl oysters and freshwater mussels; most of the ones sold are cultured and not wild. Natural pearls have been highly valued as gemstones and objects of beauty for many centuries.


Q: What is the term for the hard, round object produced within the mantle of a living shelled mollusk?

 Choices:

- ball

- root

- glass

- pearl

A:
pearl
