instruction:
Given a statement, generate a question such that the answer is contained in that statement.
question:
Humans are the dominant land animals
answer:
What are the dominant land animals?

question:
Muscles in the upper arm shrinking causes a person 's elbow to straighten.
answer:
What causes a person's elbow to straighten?

question:
teenage is a time of puberty
answer:
What is a time of puberty?