In this task, find the most appropriate number to replace the blank (indicated with _ ) and express it in words.

Q: Birds bitten by infected mosquitoes are infectious from _ to eight days.

A: four
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Q: Figure skating is like flying, but it's also like climbing hundreds of stairs in _ minutes.

A: four
****
Q: Humans are bipedal, which means they walk on _ legs.

A:
two
****