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.

Q: Sponges are subdivided into ____ classes.

A: three
****
Q: Most people stay three or four years, sometimes five or ____ years.

A: six
****
Q: All mammals have ____ limbs.

A:
four
****