Your friend tells you she thinks the constructivist perspective is wrong and race is a biological fact. she challenges you, "in fact, if race isn't biological, then how can companies determine a person's race by examining their dna

The good answer to give to your friend is that individuals has their own physical characteristics where it likely corresponds to instructions in their DNA. However, scientist are likely following a social constructed rules that focuses more on race, in determining what to look in the DNA that they are likely examining.