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]: Respiratory therapists complete two to ____ years of education.
[A]: four


[Q]: Avian kidneys have ____ kinds of nephrons.
[A]: two


[Q]: Spiders have one, two, or ____ pairs of spinnerets.
[A]:
three