Fascinating. This is different than I thought: "The variation along ethnic lines, they believe, is a reflection of genetics, not environment." Taking one exam

Fascinating. This is different than I thought: "The variation along ethnic lines, they believe, is a reflection of genetics, not environment." Taking one example that I know a little about. Korea. I would think that environmental impact would include things like the type of probiotic foods they eat - like kimchi, fermented soybeans and fermented fish would affect the flora and fauna in their mouth. Also eating habits - Koreans will often share a soup container and side dishes where everyone sticks their chopsticks and soupspoons into a shared pot, These things would affect the types of bacteria in their bodies I would think...