A whole ecosystem lives in your belly button. 你的肚脐眼中存在着一整个生态系统。
Scientists found 2,368 different species of bacteria living in belly buttons after swabbing the navels of just 60 people. 科学家在仅仅从60个人的肚脐眼中取样后就发现里面生存这2,368不同种类的细菌。