In the human body, microorganisms tend to outnumber human cells ten to one. The microorganisms are largely symbiotic and found throughout the body, though most densely in the digestive tract. In ...

Excessive sleepiness means sleeping more than usual and still feeling drowsy most of the day. You may feel sleepy and fatigued for many reasons, including lifestyle habits, weather changes, side ...

How Wild hits trails around the country, exploring the meaning of wilderness. A century ago, the U.S. set aside the first official wilderness. You'll hear stories from rangers, scientists, hikers, ...

Turn your phone into a portable planetarium, map the night sky and discover the best place and time to observe February's solar eclipse, with the best stargazing apps.