Tornadoes killed at least 17 people on Sunday and Monday. But some managed to stay safe in underground shelters like the one at right in Vilonia, Ark. Karen E. Segrave/AP hide caption

itoggle caption Karen E. Segrave/AP

Kelly Koshuta, a basketball star at James Madison High School, Vienna, Va., had surgery to repair an anterior cruciate ligament injured in 2012. Sarah L. Voisin/The Washington Post hide caption

itoggle caption Sarah L. Voisin/The Washington Post

Testosterone levels in men can go up and down throughout the day. Katherine Streeter for NPR hide caption

itoggle caption Katherine Streeter for NPR

Katherine Streeter for NPR Katherine Streeter for NPR hide caption

itoggle caption Katherine Streeter for NPR

There today, here tomorrow: A mother holds her child for a measles vaccination in Manila, Philippines, in January. Travelers are bringing measles from the Philippines to the United States. Noel Celis/AFP/Getty Images hide caption

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A woman tries electronic cigarettes at a store in Miami. Joe Raedle/Getty Images hide caption

itoggle caption Joe Raedle/Getty Images