People are identified by physiological features which categorize them into races

In the culturally diverse United States, people often identify one another's race based on skin color. Identification based on skin color is easy for U.S. Americans to do because of the migration and colonization history of North America. The idea that outward physical appearance determines one's race is also prevalent in South Africa and the U.K.^[1] One study has shown that children as young as 3 months old in the U.S. begin to racially categorize people. ^[2] The idea that physiological features, such as skin color, determine race is woven into societies and taught to children at an early age.^{[3] [2]}

[P1] Races are defined by outward appearance or other physiological features.