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: Tin has ____ allotropic forms.

Answer: two


Question: Elephants give birth to ____ calf every four to nine years on average.

Answer: one


Question: Carbon is electron deficient - it only has ____ electrons around it.

Answer:
four