Variety is the spice of life. Absent the amazing diversity of organisms that calls Earth home, it would be a deadly boring place. How did we get to a point where Komodo dragons, giraffes and butterflies all compete for space on the same planet?
When was the last time you laughed? Chances are, you've already done it today. Laughter has social, psychological and physiological functions -- some researchers are even looking to use laughs in therapy. Test who will have the last laugh: you or the Ultimate Laughter Quiz.