题目内容：
Directions: Each sentence below has one or two blanks, each blank indicating that something has been omitted. Beneath the sentence are five lettered or sets of words. Choose the word or set of words for each blank that best fits the meaning of the sentence as a whole.Handedness can be influenced and changed by social and cultural mechanisms, as can be evidenced by the fact that teachers hare been known to force children to switch from using their left hand to using their right hand for writing and that some more___________ societies show less left-handedness in their populations than other more ___________ societies.
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