Why are some people lefthanded Daniel M Abrams
>> YOUR LINK HERE: ___ http://youtube.com/watch?v=TGLYcYCm2FM
View full lesson: http://ed.ted.com/lessons/why-are-som... • Today, about one-tenth of the world’s population are southpaws. Why are such a small proportion of people left-handed -- and why does the trait exist in the first place? Daniel M. Abrams investigates how the uneven ratio of lefties and righties gives insight into a balance between competitive and cooperative pressures on human evolution. • Lesson by Daniel M. Abrams, animation by TED-Ed.
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