instruction:
Given a statement, generate a question such that the answer is contained in that statement.
question:
Butterflies have two pairs of wings for flight.
answer:
How many pairs of wings do Butterflies have?

question:
Birds use small branches and twigs to protect their offspring.
answer:
What do birds use to protect their offspring?

question:
a slide rule is used for subtracting
answer:
What rule is used for subtracting?