Why does race exists?

Question

I thought we all descended from Africa million of years ago as one...

Answer 1

Some argue that although "race" is a valid taxonomic concept in other species, it cannot be applied to humans. Many scientists have argued that race definitions are imprecise, arbitrary, derived from custom, have many exceptions, have many gradations, and that the numbers of races delineated vary according to the culture making the racial distinctions; thus they reject the notion that any definition of race pertaining to humans can have taxonomic rigour and validity. Today most scientists study human genotypic and phenotypic variation using concepts such as "population" and "clinal gradation". Many contend that while racial categorizations may be marked by phenotypic traits, the idea of race itself, and actual divisions of persons into races, are social constructs.

Answer 2

Race exists cuz Everyone loves "NASCAR"....!!!!!!!!!