It heats the air it zips through to five times the surface temperature of the sun. Still, around 90 percent of lightning-strike victims survive. Over the past three decades, lightning has killed an average of 51 people per year in the U.S. but left more than 500 injured and alive.
Computer vision syndrome. Computer vision syndrome (CVS) is a condition resulting from focusing the eyes on a computer or other display device for protracted, uninterrupted periods of time.
Knowledge center. Down syndrome (or Down's syndrome) is a chromosomal disorder caused by an error in cell division that results in an extra 21st chromosome. The condition leads to impairments in both cognitive ability and physical growth that range from mild to moderate developmental disabilities.