I never said it was 100% environmental (those are your words). I said determining the cause of high ability in things like chess is not straightforward because

I never said it was 100% environmental (those are your words). I said determining the cause of high ability in things like chess is not straightforward because of the confounding environmental factors. Just because your cherry picked example of basketball has an obvious first order physical correlation to performance (height) doesn't mean it's comparable to chess. And your example also ignores the fact that white students tend to have more avenues to access college than black students, so don't need basketball programs nearly as much.