The Fact That Immigrants from Eastern Europe, Asia, and Latin

The fact that immigrants from Eastern Europe, Asia, and Latin America tended to be shorter than native-born Americans was taken as evidence that there were inherent racial differences between these populations. However, the immigrants had children who grew up to be as tall as anyone else. Geneticists now understand that, although there can be considerable variation in height within a group due to genetics, height differences between groups are largely caused by diet. What does this demonstrate?

A) Race will always be an important way to understand physical traits.
B) There are essential differences between racial populations.
C) Some physical features, like blood type, are correlated with race.
D) Racial differences are socially constructed and not genetic.