Given scientific fact as input, generate the question from this fact such that it can be answered from the input.

Q: Constant random motion trait of particles causes even cold objects to have some thermal energy.

A: Which trait of particles causes even cold objects to have some thermal energy?
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Q: Clear mucus is secreted before ejaculation to neutralize acidic urine remaining in the urethra.

A: What is secreted before ejaculation to neutralize acidic urine remaining in the urethra?
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Q: About half of solar type of radiation is absorbed in the first 15 meters of water.

A:
About half of what type of radiation is absorbed in the first 15 meters of water?
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