Based on Franz Boas's Observation That Contact Between Neighboring Tribes

Based on Franz Boas's observation that contact between neighboring tribes has existed since humanity's beginnings and covered enormous areas, it can be argued that

A) biology, not culture, was responsible for the vast majority of human diversity.
B) language must have originated among the Neandertals.
C) general anthropologists were wrong to focus too much attention on biology.
D) cultures should not be treated as isolated phenomena.
E) even the earliest foragers engaged in warfare.