so that in this respect, as well as in size, natural selection might have secured and fixed any advantageous variation.
Australiako Brontze-kukuaren arrautzak, Ramseyk dioenez, ezohiko ezberdintasuna dute kolorean; hainbesterainokoa, non honetan, baita tamainuan ere, hautespen naturalak aldakuntza abantailatsuren bat segurta eta finka zezakeen.