Final answer:
Biological anthropologists argue that the concept of race is not scientifically valid due to genetic variation and the arbitrary nature of racial classification, as well as the social construction of race. Skin color, for instance, varies along a spectrum and is not a reliable determinant of race.
Step-by-step explanation:
Biological anthropologists argue that the concept of race is not scientifically valid due to three characteristics of human variation. First, genetic markers for physical characteristics like skin color and hair texture align with only a few of the thousands of DNA markers, making it difficult to categorize people into racial groups. Second, there is more genetic variation within racial categories than between them, meaning that the lines we draw to classify races are arbitrary. Third, the notion of race is a social construction, created by people and subject to change. For example, anthropologist Nina Jablonski demonstrates that skin color varies along a spectrum, with individuals having skin of every possible shade between pinkish beige and dark brown. This variation is due to humans evolving to adapt to different levels of sunlight exposure. Overall, biological anthropology shows that race is an inaccurate and arbitrary way to classify humans.