How variation exist without variation?

developmental variation

the tendency among similar organism to differ from each other to some degree..

Evolution of any kind can not be accomplished without mistakes ... other wise everything will continue to be exactly the same and die of the same ailments ...

retain some elements of the theme

Consider two variables x and y.If x varies directly as y then y = cx where c is some constant of variation. This means that whenever x increases, y increases and it increases by c times as much as...