G+: Old tools — and poison — push back Stone Age 20,000 years http://www.msnbc.msn.com/id/48403738/ns...

Old tools — and poison — push back Stone Age 20,000 yearshttp://www.msnbc.msn.com/id/48403738/ns/technology_and_science-science/

Old tools — and poison — push back Stone Age  20,000 years

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Originally posted on Google+. Join the conversation at Old tools — and poison — push back Stone Age 20,000 years http://www.msnbc.msn.com/id/48403738/ns...

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