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

[EX Q]: Muscles in the upper arm lengthen a person's elbow.
[EX A]: What lengthen a person's elbow?

[EX Q]: hunting requires detecting an animal
[EX A]: What is required for hunting?

[EX Q]: neurons transmit signals to cells
[EX A]:
What transmits signals to cells?