Stem cells are unspecialized cells that can reproduce themselves for long periods of time using cell division, but are also capable of differentiating into almost any type of specialized cell. This unique ability makes them ideal for use in regenerative medicine. Adult stem cells are derived from umbilical cord blood and bone marrow. Embryonic stem cells are also used in medical research, but their use is more controversial. Why is there an ethical debate surrounding embryonic stem cell use?
John F. Kennedy
Back in the day
USA Today was founded in 1982 with the goal of providing an alternative to relatively colorless, copy-oriented publications like The New York Times. The paper, known for synthesizing news down to easy-to-read-and-comprehend stories, is colorful and bold, with many large diagrams, charts, and photographs. USA Today boasts the second widest circulation of any English-language broadsheet, behind what publication?
Born on a day like today
Marco Polo was a Venetian trader and explorer who, together with his father NiccolÃ² and his uncle Maffeo, was one of the first Westerners to travel the Silk Road to China. Polo helped generate extraordinary interest in the Far East among Europeans, and his book, Il Milione, was an instant hit at a time when books had to be painstakingly copied by hand. What famous explorer carried a heavily annotated copy of Polo's book?