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Home Q & A Board Biology-Related Homework Help General Biology
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Guido Guido
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7 years ago
Smiling when happy seems to be an expression common to all human societies, suggesting that this behavior is probably
A) genetic in origin.
B) learned.
C) altruistic.
D) based on social standing.
Textbook 
Biology: Life on Earth

Biology: Life on Earth


Edition: 10th
Authors:
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skeledentskeledent
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7 years ago
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Guido Author
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7 years ago
This helped my grade so much Perfect
patod1
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Yesterday
Thanks for your help!!
MAry1395
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2 hours ago
You make an excellent tutor!
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