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

Q: Passage: Steel is an example of an alloy. An alloy is a mixture of a metal with one or more other elements. The other elements may be metals, nonmetals, or both. An alloy is a solid solution. It is formed by melting a metal and dissolving the other elements in it. The molten solution is then allowed to cool and harden. Several other examples of alloys and their uses are shown in Figure below . You can learn about an amazing alloy called memory wire at the URL below. If you have braces on your teeth, you may even have this alloy in your mouth!. Answer: an alloy

A: A mixture of a metal with one or more other elements is called?
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Q: Passage: Great volcanic explosions and glowing red rivers of lava are fascinating. All igneous rock comes from magma or lava. Remember that magma is molten rock that is below Earth's surface. Lava is molten rock at Earth's surface. Answer: magma or lava

A: Where does all igneous rock come from?
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Q: Passage: In ferns, the sporophyte is dominant and produces spores that germinate into a heart-shaped gametophyte. Answer: heart-shaped

A:
What shape is the gametophyte in ferns?
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