This computer-enhanced barium contrast X-ray shows colon cancer in red. Researchers have been trying to figure out what looks to be a decade-long rise in colon cancer among people younger than 50.
Scott Camazine/Science Source
Andie Vaught grasps a stress toy in the shape of a truck as she prepares to have blood drawn as part of a clinical trial for a Zika vaccine at the National Institutes of Health in Bethesda, Md., in November 2016.
Allison Shelley/The Washington Post/Getty Images
In a cluster of glowing human stem cells, one cell divides. The cell membrane is shown in purple, while DNA in the dividing nucleus is blue. The white fibers linking the nucleus are spindles, which aid in cell division.
Allen Institute for Cell Science
Diane, a 4-year-old chimpanzee, relaxes in the trees at the Chimp Haven sanctuary in Keithville, La., on Aug. 25, 2014. She is one of many chimps who have been moved here from the New Iberia Research Center in Lafayette, La.
Ronald Davis cares for his 31-year-old son, Whitney Dafoe. Dafoe is seriously ill with ME/CFS. His father, a Stanford University professor, is organizing a study of the disorder.
Courtesy of Ashley Davis
Feces contain digested food residue and a wide variety of microorganisms, mostly bacteria, that are adapted to life in the intestines. The gases the microbes produce could help doctors and scientists track and understand changes related to health.
Scimat Scimat/Photo Researchers/Getty Images