The author thinks that we have everything, our living conditions have improved, our mood is naturally good, and we also pay attention to health preservation to make ourselves healthy and strong. The ancestors of this species are primitive people who lived in the cold areas of the north. Their body hair is developed and their nasal cavity is long and narrow, which is the characteristic of adaptation and evolution. In order to resist the cold, they tend to be heavier and stronger, and they mainly eat meat. Yellow people are primitive people living in the middle latitudes. The climate in this area is more suitable, and there are many kinds of plants, most of which feed on grains. The body shape is naturally different from that of white people who are mainly meat-eaters. Black people live in low latitudes, with hot climate and fast metabolism, so it is impossible to have a strong body shape. At present, pure blacks in Africa are still relatively thin. Blacks in western countries are often not pure blacks, but have white blood. Many whites are genetically recessive and many are married.