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: the looseness of soil increases the amount of oxygen in that soil
If soil is loose, it makes it what for oxygen to get in?

Fact: An example of a fossil is a footprint in a rock
I found an impression of bird's feet in a rock?

Fact: if an object reflects more light then that object is more easily seen
Which of the following reflects the most light?