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

Answer: four


Question: Seasonal records indicate that, in most years, ____ generations occur.

Answer: two


Question: People are born with ____ kidneys.

Answer:
two