instruction:
Given scientific fact as input, generate the question from this fact such that it can be answered from the input.
question:
Clear mucus is secreted before ejaculation to neutralize acidic urine remaining in the urethra.
answer:
What is secreted before ejaculation to neutralize acidic urine remaining in the urethra?


question:
Solids are categorized by the forces holding the individual atoms, ions, or molecules together.
answer:
What is categorized by the forces holding the individual atoms, ions, or molecules together?


question:
Tidal change is the difference between the daily high and the daily low.
answer:
What is the difference between the daily high and the daily low?