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.

Box turtles are mature and capable of mating at ____ years old.
five

Early childhood refers to the time period between birth and ____ years of age.
eight

Most organ systems are operational in the fetus by ____ to six months.

four