instruction:
Given a scientific passage and an answer, generate a question for the given answer.
question:
Passage: Simple carbohydrates can be classified in terms of chain length. Answer: simple
answer:
Which carbohydrates can be classified in terms of chain length?

question:
Passage: Adulthood is divided into the stages of early, middle, and late adulthood. Answer: three
answer:
Adulthood is divided into how many stages?

question:
Passage: The law of conservation of mass states that matter cannot be created or destroyed. Answer: destroyed
answer:
The law of conservation mass states that matter cannot be created or what?