Given a scientific passage and an answer, generate a question for the given answer.

Q: Passage: Mollusks live in most terrestrial, freshwater, and marine habitats. However, the majority of species live in the ocean. They can be found in both shallow and deep water and from tropical to polar latitudes. They have a variety of ways of getting food. Some are free-living heterotrophs. Others are internal parasites. Mollusks are also eaten by many other organisms, including humans. Answer: ocean

A: Where do the majority of species live?
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Q: Passage: Blue cheese is blue because of the fungus growing throughout it. Answer: blue

A: What color is the fungus in blue cheese?
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Q: Passage: Mother of pearl is also known as nacre. Nacre is the iridescent inner shell layer. It can be found in buttons, watch faces, knives, guns, and jewelry. It is also used to decorate various musical instruments. Answer: nacre

A:
What is another name for mother of pearl?
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