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

[EX Q]: statement: A magnifying glass is an optical tool., question: What is magnifying glass?
[EX A]: optical tool

[EX Q]: statement: eagle egg shells are natural., question: What type of egg shells are natural?
[EX A]: eagle

[EX Q]: statement: upper arm muscles contracting causes a person 's elbow to elongate, question: What muscle contracting causes a person's elbow to elongate?
[EX A]:
upper arm