"I was one of these teenagers, and so I know how difficult it can be to break this habit when it's been with you for a long time,".

VOA: standard.2009.06.22

That's how long it took for an international team of scientists to excavate and analyze the fossilized skeleton of a 4.4 million year old human ancestor, Ardipithecus ramidus, which was discovered in Ethiopia.

VOA: standard.2009.12.24