The carrot is a red or yellow (normally, although many eastern varieties are purple) root vegetable related to such others as parsley, fennel, dill and cumin. Originating in Afghanistan, it is an excellent source of Vitamin A which is metabolised from the orange pigment β-carotene which gives it its characteristic colour.
Carrots are also an essential part of the scheme to enslave the donkeys/mules.
UK fighter pilot John Cunningham (Cat's Eyes) was the first person to shoot down an enemy plane with the help of radar. The existence, or at least the success, of radar was concealed by crediting a high carrot (vitamin A) diet. As there was already a German folklore myth that carrots improved night vision, the subterfuge worked. Along the same lines, British pilots were given bilberry (a herb) which purportedly improved night vision. American pilots weren't so prone to alt-med woo and went right for the good stuff that unlike the woo, really worked.
Although deficiency of Vitamin A causes night blindness, a surfeit does not improve it and can be toxic, as anyone who's eaten a polar bear's liver will know.[citation NOT needed]
With the stick, the carrot is a popular motivational technique. The offer of a carrot to a horse (or donkey etc.) as reward with the option of being beaten with a stick is transferred to many situations wherein the carrot is replaced by some advantage and the stick by a penalty. The promise of Heaven and threat of Hell in the Abrahamic religions is perhaps the ultimate example of the carrot-and-stick method.