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

[EX Q]: Passage: Matter can be classified as transparent, translucent, or opaque depending on how it interacts with light. Answer: opaque
[EX A]: Depending on how matter interacts with light, it can be classified as transparent, translucent, or what?

[EX Q]: Passage: Volatile organic compounds (VOCs) are carbon compounds such as methane. VOCs are released in many human activities, such as raising livestock. Livestock wastes produce a lot of methane. Answer: methane
[EX A]: The waste of cows releases a lot of which type of gas?

[EX Q]: Passage: The hard drive is a magnetic disc that provides long-term storage for programs and data. Answer: hard drive
[EX A]:
What device is a magnetic disc that provides long-term storage for programs and data?