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

Q: Flatworms exhibit _ forms of life styles, free-living and parasitic.

A: two
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Q: Willow flycatchers have a lifespan of _ to four years.

A: three
****
Q: Most movements require the activation of very few muscles, around _ percent or ten at the most.

A:
five
****