"those animals which acquire habits of mutual aid are undoubtedly the fittest to survive"
"mutual aid was the chief factor of progressive evolution."
martes, 20 de octubre de 2009
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If people brushed their teeth as often as they claimed, and used the amount of toothpaste they indicated, three times as much toothpaste would be sold in the United States than is actually sold (Barringer, 1993).
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