Sentence:  As we remarked once before, there are two extreme views with respect to life, one attributing everything to the environment, the other to inherent abilities. If, for example, an unusual number of distinguished men are born and reared in the same locality, the <WSD>environmentalists</WSD> assert that the causes for their appearance were entirely external and that had their parents changed habitats with those residing elsewhere the result would have been the same, except that the family names of these eminent men would have been different. 
Meaning of the word marked with <WSD> tags:  One who holds the view that environment, rather than heredity or culture, is the primary factor in the development of an individual or group.