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: Neutrons consist of one up quark and ____ down quarks.

Answer: two


Question: Prairie dogs bear four or ____ young per litter.

Answer: five


Question: Ozone is a molecule composed of ____ atoms of oxygen.

Answer:
three