Given a fact, create a question that can be answered using the fact. Construct the question such that it is unambiguous, has a unique answer and the answer can be given using the fact.

Fact: a magnet attracts ferromagnetic metals through magnetism
A magnet would attract a?

Fact: the solar system contains the moon
In the 60's people watched on TV while for the first time people walked on?

Fact: as the amount of rainfall increases in an area , the amount of available water in that area will increase

After a storm, a glass vial with markings on it can tell?