TASK DEFINITION: Given a statement and question, generate the answer to the question such that the answer is contained in the statement.
PROBLEM: statement: muscles contracting cause a person's arm to straighten, question: What causes a person's arm to straighten?

SOLUTION: muscles contracting

PROBLEM: statement: hornworts occupy niches in wet habitats, question: What occupy niches in wet habitats?

SOLUTION: hornworts

PROBLEM: statement: a beak is used for catching maggots by birds, question: What do birds use a beak to catch?

SOLUTION:
maggots