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

Evolution occurs by natural selection, a process whereby better-adapted members pass along their traits, according to darwin.
Evolution occurs by what process whereby better-adapted members pass along their traits, according to darwin?

Clear mucus is secreted before ejaculation to neutralize acidic urine remaining in the urethra.
What is secreted before ejaculation to neutralize acidic urine remaining in the urethra?

By exploding bolts the space probes get separated from their launchers.

By exploding what the space probes get separated from their launchers?