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: Some species bear living offspring only every three to ____ years.

Answer: five


Question: Power is derived from ____ sources, money and people.

Answer: two


Question: Sound waves travel about ____ times as fast in water and about ten times as fast in steel.

Answer:
four