This human-scale lab rat cage is parked near a skate park in Denver, Colo., to make a point about the lack of science on marijuana. Richard Feldman Studio/Sukle Advertising and Design hide caption

itoggle caption Richard Feldman Studio/Sukle Advertising and Design

Young poets Monica Mendoza (clockwise from top left), Erica Sheppard McMath, Obasi Davis and Gabriel Cortez have written about how Type 2 diabetes affects their families and communities. Courtesy of The Bigger Picture hide caption

itoggle caption Courtesy of The Bigger Picture

PCR tests like this can tell if a virus is an enterovirus, but they can't ID the new virus that has caused a surge in serious respiratory infections. BSIP / Science Source hide caption

itoggle caption BSIP / Science Source

Helen Down holds her 14-month-old daughter, Amelia, for an MMR shot in Swansea, Wales, April 2013. The vaccination was in response to a measles outbreak. Geoff Caddick/AFP/Getty Images hide caption

itoggle caption Geoff Caddick/AFP/Getty Images