Given a sentence, fill out the missing word with a 'no' or a number (between zero and ten). You should write the numbers with english alphabet, like: four instead of 4.

[EX Q]: Sexual maturity is reached at ____ years, and females calve every other year.
[EX A]: four

[EX Q]: Mature birds boast a wing span of ____ feet.
[EX A]: six

[EX Q]: Wolves attain sexual maturity at about ____ years old.
[EX A]:
two