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 occurs at ____ to four years for females and four to five years for males.
[EX A]: three

[EX Q]: Birds have ____ beak, two wings, and two feet.
[EX A]: one

[EX Q]: Breast cancer has ____ stages.
[EX A]:
four