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]: Most organ systems are operational in the fetus by ____ to six months.
[A]: four


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


[Q]: Yield is where the ____ crops have parted ways.
[A]:
two