Indian schoolchildren write English alphabets on slates at a primary school outside Hyderabad in June. India is on track to overtake China as the most populous nation in just 16 years. Noah Seelam/AFP/Getty Images hide caption

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An Afghan health worker administers the polio vaccine to a child during a vaccination campaign in Kabul, Afghanistan, in 2010. Majid Saeedi/Getty Images hide caption

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A study of Ugandans found antiretroviral drugs can extend the lifespans of people with HIV to nearly normal lengths. Adek Berry/AFP/Getty Images hide caption

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Mourners attend a memorial service for recent cholera victims in Haiti that took place Wednesday in Savanette, an isolated community in the mountains outside Mirebalais, Haiti. Cate Oswald/Partners in Health hide caption

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A man pushes a friend in a wheelchair following an event in Beijing to raise awareness of accessibility issues for the disabled. Ng Han Guan/ AP Photo hide caption

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Lettuce at an organic vegetable farm in Teltow, Germany. Organic farmers in Germany are reporting a surge in demand for lettuce and cucumbers in the wake of an outbreak of E. coli after health officials warned people not to eat cucumbers, lettuce and tomatoes, though organic produce may not necessarily be safer. Sean Gallup/Getty Images hide caption

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Most of the stillbirths worldwide happen in south Asia and sub-Saharan Africa, and at least half of them take place during labor or birth. iStockphoto.com hide caption

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