It has often been asked, if natural selection be so potent, why has not this or that structure been gained by certain species, to which it would apparently have been advantageous?
Sarri galdetu izan da: hautespen naturala hain ahaltsua bada, zergatik ez du espezie jakin batek itxuraz abantailatsu zitzaiokeen egitura hura edo bestea bereganatu?