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

[Q]: Muscles in the upper arm shrinking causes a person 's elbow to straighten.
[A]: What causes a person's elbow to straighten?


[Q]: Standing still is used for avoiding predators.
[A]: What is used for avoiding predators?


[Q]: Octopuses spray a cloud for hiding from whales
[A]:
What sprays a cloud for hiding from whales?