Given scientific fact as input, generate the question from this fact such that it can be answered from the input.
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Question: The mesopause is at the top of the mesosphere.

Answer: What is at the top of the mesosphere?

Question: Radioactivity is the release of particles and/or energy from the nucleus of an atom.

Answer: What is the release of particles and/or energy from the nucleus of an atom described as?

Question: Warm, humid climate allowed life to expand and diversify during the early cambrian period.

Answer:
What allowed life to expand and diversify during the early cambrian period?