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: Yellow fever begins suddenly after an incubation period of three to ____ days.

Answer: five


Question: Tuataras reproduce very slowly, sometimes taking ____ years to reach sexual maturity.

Answer: ten


Question: Irrigated land is almost ____ times as productive as rainfed cropland.

Answer:
three