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: sedimentary rocks are formed from sediment compacting together
At the beach you are likely to find this type of stone:?

Fact: a windmill does not create pollution
What is safest to breathe around?

Fact: adding heat to an object sometimes causes chemical reactions

A chemical reaction may occur when _____ is added to an object.?