Given a statement, generate a question such that the answer is contained in that statement.

[Q]: steel is used for bearing weight by suspension bridges
[A]: What is steel used for bearing weight?


[Q]: muscles contracting cause a person's arm to straighten
[A]: What causes a person's arm to straighten?


[Q]: Smog has been linked with lung disease.
[A]:
Smog has been linked to what type of disease?