Final answer:
Race cannot be biologically identifiable and there is more variation within racial categories than between them.
Step-by-step explanation:
The controversy surrounding race as a biological category refers to the fact that race cannot be biologically identifiable. While there are genetic markers for physical characteristics like skin color, these markers do not align with the convenient categories we use to divide people into racial groups. Biological anthropologists have shown that any way you draw the lines, there will be more variation within racial categories than between them.