Puzzle 20: Hatch
TRIVIA
The old riddle asks the question, "Which came first, the chicken or the egg?"
The idea of the riddle is that all chickens come from eggs, but to get eggs you must have a chicken to lay them.
Dinosaurs laid eggs, so we know that eggs existed long before the first chickens, but if you consider the egg in the riddle to refer specifically to a chicken's egg, then the puzzle remains. Have a look at the linked article and draw your own conclusions on this puzzle.
New Scientist: Which came first, the chicken or the egg?