Genetic analyses show that all varieties of domestic dogs are descendants of the wolf, and studies show that wolves have brains nearly twice the size of those of dogs of comparable size and that wolves are correspondingly more intelligent. But given that there are about 38 thousand wolves in North America, while there are over 50 million domestic dogs, it is obvious that dogs have been amply compensated, from an evolutionary standpoint, for the losses produced by their association with humanity. Which one of the following principles most helps to justify the reasoning above? ['Evolutionary success of a species should be measured by the number of individuals in that species rather than by the abilities of those individuals.', "It need not be the case that an organism's chances of survival will be enhanced by its having a larger brain and a higher intelligence.", 'Evolutionary success is not always attained by the group or species whose members are most fit.', 'Evolutionary success of a species is determined by genetic rather than environmental factors.']