Ask a question, get an answer. What allows you to achieve subject matter background in science and mathematics is good teaching of those subjects. That's the point of the international educational achievement comparisons. They show, as do studies of high-ability United States students,

http://www.hks.harvard.edu/pepg/PDF/Papers/PEPG10-19_Hanushe...

http://www.jkcf.org/news-knowledge/media-coverage/no-child-l...

that what limits educational achievement (and thus preparation for college studies) of many United States students is not limits in their capacity to learn, but limits in the curriculum they were taught. The United States school system doesn't step up to INCREASE the ability of the national populace the way many other school systems do better.

After edit: If you actually want to learn something serious about ethnicity in its many manifestations around the world, start here

http://en.wikipedia.org/wiki/User:WeijiBaikeBianji/Anthropol...

and keep reading until you've read a dozen or so of those books, to get past the many errors found in most blog posts on the subject.